### Am I affected? Users are affected if all of the following are true: - Their application uses `better-auth` at a version below the patched release. - Their application enables `oidcProvider()` from `better-auth/plugins/oidc-provider` or `mcp()` from `better-auth/plugins/mcp` (the mcp plugin delegates to `oidcProvider` and inherits both defaults). - For the algorithm-negotiation impact: relying parties of the application's OIDC server use a JWT verification library that performs algorithm negotiation from the discovery document without pinning to a specific signing algorithm. - For the PKCE impact: the authorization URL is exposed to any party other than the user agent and the application's OP. If the application only uses `@better-auth/oauth-provider` (the canonical replacement) and have not enabled the legacy plugins, it is not affected. The new package's discovery document excludes `none` and its authorize schema rejects `plain` at parse time. Fix: 1. Upgrade to `better-auth@1.6.11` or later. 2. Migrate from the deprecated `oidcProvider` and `mcp` plugins to `@better-auth/oauth-provider` when feasible. 3. If developers cannot upgrade their applications, see workarounds below. ### Summary The legacy `oidcProvider` and `mcp` plugins exhibit two related defects in their OIDC discovery and authorize surfaces. The discovery document advertises `"none"` in `id_token_signing_alg_values_supported` (and, for `mcp`, in `resource_signing_alg_values_supported` on the OAuth protected-resource metadata). Any relying party that performs algorithm negotiation from this metadata without pinning to a real signing algorithm may accept unsigned tokens. PKCE `plain` is enabled by default. The runtime gate in the authorize handler accepts `code_challenge_method=plain` under this default, and a missing `code_challenge_method` parameter is silently downgraded to `"plain"` before the allowlist check. Discovery advertises `code_challenge_methods_supported: ["S256"]`, contradicting the runtime acceptance of `plain`. RFC 9700 §2.1.1 (OAuth 2.1) explicitly forbids `plain`. ### Details The metadata builders unconditionally inject `"none"` into the alg list. The runtime authorize gate is structured so a buggy client that strips the `code_challenge_method` parameter still enters the plain code path because the handler rewrites the missing value to `"plain"` before the allowlist check fires. `@better-auth/oauth-provider` (the deprecation target for `oidcProvider`) is not affected by either defect. The metadata builder uses a `JWSAlgorithms` type union that structurally excludes `"none"`. The authorize schema is `code_challenge_method: z.literal("S256").optional()`, which rejects `plain` at parse time. ### Patches Fixed in `better-auth@1.6.11`. The legacy `oidcProvider` and `mcp` plugins now: - Drop `"none"` from `id_token_signing_alg_values_supported` (both plugins) and from `resource_signing_alg_values_supported` (`mcp`). Discovery no longer advertises the unsigned-token option. - Default `allowPlainCodeChallengeMethod` to `false`. A request that explicitly passes `code_challenge_method=plain` is rejected with `invalid_request` unless the integrator opts in. - Reject a `code_challenge` without an accompanying `code_challenge_method` instead of silently rewriting the missing value to `plain`. Clients that send `code_challenge` must also send `code_challenge_method=S256`. Discovery and runtime behavior align on `S256` only by default. Integrators who must keep plain PKCE for legacy clients can restore the previous shape with `oidcProvider({ allowPlainCodeChallengeMethod: true })` (and likewise for `mcp`). With the opt-in set, a request that omits `code_challenge_method` is treated as `plain` again, preserving backwards compatibility while keeping the secure default for everyone else. Both legacy plugins are deprecated long-term; the recommended migration is `@better-auth/oauth-provider`, which never advertised `none` or accepted plain PKCE. ### Workarounds If developers cannot upgrade their applications immediately: - **Disable plain PKCE explicitly**: set `oidcProvider({ allowPlainCodeChallengeMethod: false })` (and the equivalent on `mcp`). Closes the runtime acceptance of `plain` even though the silent downgrade still rewrites missing methods. - **Override the metadata** to drop `"none"` from `id_token_signing_alg_values_supported`. For `oidcProvider`, pass `metadata: { id_token_signing_alg_values_supported: ["RS256"] }`. For `mcp`, set the same on `options.oidcConfig.metadata`. Verify by curling the `.well-known` endpoint. - **Migrate to `@better-auth/oauth-provider`**: the package is the deprecation target and is unaffected by both defects. ### Impact - **Algorithm-negotiation downgrade**: relying parties that read the discovery document without pinning may accept unsigned (`alg: "none"`) tokens. - **Authorization-code interception**: PKCE `plain` does not protect the authorization code if the URL leaks (Referer headers, browser history, screen capture, proxy logs). PKCE `S256` is what protects against that exposure; with `plain` the protection is absent. - **OAuth 2.1 / RFC 9700 non-conformance**: deployments shipping the defaults are non-compliant with current standards. ### Credit Reported by @subhanUmer. ### Resources - [CWE-327: Use of a Broken or Risky Cryptographic Algorithm](https://cwe.mitre.org/data/definitions/327.html) - [CWE-757: Selection of Less-Secure Algorithm During Negotiation](https://cwe.mitre.org/data/definitions/757.html) - [CWE-1188: Insecure Default Initialization of Resource](https://cwe.mitre.org/data/definitions/1188.html) - [RFC 9700 §2.1.1: PKCE](https://datatracker.ietf.org/doc/html/rfc9700#section-2.1.1) - [RFC 9700 §2.1.2: Token Replay Prevention](https://datatracker.ietf.org/doc/html/rfc9700#section-2.1.2) - [RFC 8414 §2: Authorization Server Metadata](https://datatracker.ietf.org/doc/html/rfc8414#section-2)
PoC: xiaomi15-dada-cve-2026-64560
Device-bound CVE-2026-64560 adaptation for Xiaomi 15 dada OS4.0.0.8
PoC: cve-2026-32475-elementor-pro-lab
A/B Docker lab + PoC for CVE-2026-32475 (Elementor Pro Forms unauthenticated arbitrary file upload -> RCE via validation/move loop desync)
PoC: CVE-2026-58138
CVE-2026-58138
PoC: CVE-2026-41940
cPanel & WHM - Authentication Bypass via Session-File CRLF Injection
PoC: CVE-2024-12356
Unauthenticated RCE detector + RCA for BeyondTrust Remote Support / PRA (CVE-2024-12356 + CVE-2025-1094)
PoC: CVE-2026-85046
CVE-2026-85046
PoC: CVE-2026-62735
Windows HTTP.sys integer overflow -> nonpaged pool overflow LPE PoC (CVE-2026-62735): crash + full SYSTEM exploit; for authorized testing
PoC: CVE-2026-82329-JFrog-Artifactory-Auth-Bypass
CVE-2026-82329 — JFrog Artifactory (self-hosted) Auth Bypass
PoC: CVE-2026-65349
CVE-2026-65349 PoC — getattrlist OOB write in vfs_attr_pack_internal (iOS 26.6 / 23G71)
PoC: CVE-2026-65343
CVE-2026-65343 PoC — AppleKeyStore OOB read → KASLR defeat (iOS 26.6 / 23G71)
PoC: CVE-2026-65330
CVE-2026-65330 PoC — setxattr PAC bypass via fixed #0x307a diversifier (iOS 26.6 / 23G71)
PoC: CVE-2026-64788
CVE-2026-64788 PoC — IOGPUFamily Use-After-Free (iOS 26.6 / 23G71)
PoC: CVE-2026-52774-YESWIKI-XSS
a reflected XSS vulnerability in YesWiki's Bazar widget handler.
PoC: netty-http2-check
CVE-2025-55163 / CVE-2026-56819: offline checker for the 7 netty-codec-http2 CVEs. Tells you which ones you are exposed to, and the one version that fixes all seven (4.1.136.Final / 4.2.16.Final) - written on none of the advisories. Does not scan pom.xml on purpose: WebFlux pulls it in transitively.
PoC: CVE-2026-0920
A PoC exploit for CVE-2026-0920 - LA-Studio Element Kit / Unauthenticated Privilege Escalation
PoC: CVE-2026-84645
Jenkins PersistenceRoot Deserialization RCE (SECURITY-3972) — PoC & analysis. Requires Item/Configure; affects weekly <= 2.579 / LTS <= 2.568.2
PoC: cyberthreat_DBSproject
threat = { "id": "CVE-2026-0001", "title": "Apache HTTP Server Remote Code Execution", "vendor": "Apache", "product": "HTTP Server", "description": "A vulnerability in Apache HTTP Server allows remote attackers to execute arbitrary code.", "cvss": 9.8, "kev": True, "published": "2026-06-30" }
PoC: CVE-2026-6471
CVE-2026-6471
PoC: CVE-2026-75865
Unauthenticated arbitrary file upload -> RCE in WPLP Cookie Consent (gdpr-cookie-consent) <= 4.4.1 - technical write-up and PoC
PoC: CVE-2026-32475
CVE-2026-32475 PoC : Elementor Pro Unauthenticated Arbitrary File Upload to RCE
PoC: CVE-2023-42793-TeamCity-Unauthenticated-RCE
A PoC and automated version detection/exploit tool for JetBrains TeamCity Authentication Bypass & RCE (CVE-2023-42793).
PoC: cve-2026-6471-postgres-logical-decoding-dlopen
postgres CVE-2026-6471 Exploit
PoC: gpgsm-cve-2026-57062-cms-gcm-short-tag
gpgsm CVE-2026-57062 exploit POC
PoC: CVE-2025-4255---Buffer-Overflow
Exploit Framework for CVE-2025-4255
PoC: gha-lab-4a8fad8536
Security-research lab reproducing CVE-2026-39382 (GHSA-5jxf-vmqr-5g82): command injection in dbt-labs reusable workflow open-issue-in-repo.yml, driven by a dbt-core-style docs-issue.yml caller
PoC: gha-lab-ed7a1740c4
Security-research lab: controlled reproduction of GHSA-3g6g-gq4r-xjm9 / CVE-2026-35580 (GitHub Actions workflow_dispatch input shell injection) against a pinned snapshot of NationalSecurityAgency/emissary
PoC: gha-lab-85f022290a
Research lab reproduction of CVE-2026-34243 (GHSA-r4fj-r33x-8v88): command injection via issue_comment.body in .github/workflows/comment.yaml — snapshot of njzjz/wenxian@ca4e04de86aa970c0e3cb1c7f2bd103d339fbe51
PoC: gha-lab-9b5e3ccfbe
Security-research lab: reproduction of CVE-2026-33475 (GitHub Actions script injection via PR branch name in deploy-docs-draft.yml), snapshot of langflow-ai/langflow
PoC: research-cve-2026-85649
[MIRROR] The CVE-2026-85649 Security Research Publication.
PoC: gha-lab-61c59f4acb
Security-research lab: controlled reproduction of CVE-2026-33075 (pwn request in labring/FastGPT preview-image workflow, pull_request_target + checkout-of-fork + privileged buildx push)
PoC: gha-lab-3f1ff30e9c
Authorized security-research lab reproducing CVE-2026-31852 (jellyfin/jellyfin-ios pull_request_target pwn in code-quality.yml) — isolated snapshot, not the upstream project
PoC: gha-lab-ca4fa82ac5
Security-research lab: reproduction of CVE-2026-29075 (GHSA-3j55-5q6x-2h48) in mesa/mesa benchmarks.yml pull_request_target workflow — single-commit snapshot for authorized vulnerability reproduction.
PoC: gha-lab-6c3094af9e
Authorized security-research lab reproducing CVE-2026-27941 (pwn request in pull_request_target workflows) — snapshot of openlit/openlit
PoC: gha-lab-a7f6217d26
Security-research reproduction of CVE-2026-27938 / GHSA-4q9f-mjxf-rx7x (GitHub Actions expression injection in release workflows) — snapshot of wp-graphql/wp-graphql at b216fe22f3a119f256511ec7353f536fee6886ac
PoC: cve-2026-19900-PoC
cve-2026-19900-PoC
PoC: CVE-2026-85769
Heap out-of-bounds read in libtpms TPM 2.0 state deserialization — CVE-2026-85769
PoC: CVE-2026-19632
Unauthenticated account takeover PoC for TranslatePress Multilingual <= 3.3.1 (WordPress)
PoC: CVE-2026-11613
Divi Ajax Filter <= 5.1.2 Unauthenticated Local File Inclusion via 'custom_loop_template'
PoC: gha-lab-25b7988758
Authorized security-research reproduction of CVE-2026-27701 / GHSA-xh9w-5859-x97j (live-codes/livecodes @ 8017e01): untrusted PR title interpolated into i18n-update-pull github-script block.
PoC: copy-fail-CVE-2026-31431-cpp
https://github.com/theori-io/copy-fail-CVE-2026-31431 but ported to c++ for fun
PoC: CVE-2026-83548-checker
Non-intrusive detector for SonicWall SMA 1000 exposure to CVE-2026-83548/-83549 (version/patch-state check; no exploitation)
PoC: gha-lab-b16a4f3554
Security-research lab: CVE-2026-24480 pull_request_target pre-commit RCE in qgis/QGIS (snapshot at vulnerable commit)
PoC: Yordam-Kutuphane-Otomasyonunda-Coklu-HTML-Enjeksiyonu
CVE-2026-77818 - Yordam Kütüphane Otomasyon Sistemi - Üç ayrı noktada yansıtılmış HTML enjeksiyonu, form action ele geçirme ve kimlik bilgisi hırsızlığı (CWE-79)
PoC: jsherp-user-info-idor
VulDB advisory: jshERP authenticated /user/info IDOR and password-digest replay after CVE-2025-60800
PoC: gha-lab-7927d7d06f
Security-research lab reproducing CVE-2026-22869 (pwn) — arbitrary code execution in privileged pull_request_target run via npx local-bin hijack, snapshot of eigent-ai/eigent @ 2a406536
PoC: cve-2026-31431
PoC for CVE-2026-31431
PoC: gha-lab-b5c1313658
Authorized security-research lab reproducing CVE-2026-1699 (pwn request in preview.yml) — snapshot of eclipse-theia/theia-website
PoC: CVE-2026-63077
CVE-2026-63077 - Unauthenticated RCE exploit for JetBrains TeamCity via Agent Polling Deserialization. Supports mass scanning, multi-threading, and interactive shell. For authorized security testing only.
PoC: CVE-2026-6471
CVE-2026-6471 - Draft or TODO
PoC: CVE-2026-73554
CVE-2026-73554 - Draft or TODO
PoC: CVE-2026-19516
CVE-2026-19516
PoC: gha-lab-51c6b6d0a0
Lab reproducing CVE-2025-67727 (parse-community/parse-server ci-performance.yml pull_request_target RCE at e78e58d) — authorized security research
PoC: gha-lab-6904b2ccbe
Security-research lab: reproduction of CVE-2025-61584 (GHSA-9g7x-737f-5xpc) — command injection via github.head_ref in pull_request_target workflow (.github/workflows/pr.yml)
PoC: CVE-2026-85046-Patch-confusion-zero-day-vulnerability-in-Google-Chrome-s-V8-engine
Conceptual C++ patch and structural analysis for CVE-2026-85046, a critical type confusion zero-day vulnerability in Google Chrome's V8 engine
PoC: cve-disclosures
CVE-2024-57551, CVE-2024-57552, CVE-2024-57553 advisories by Aman Bahiniya
PoC: unit-01-severity-vs-risk-reflection
cve-2026-25524 Holds no customer payment data, no monitoring in place, monitored 24/7 The CVSS score is technically serious, but it doesn't tell how exposed it is, weather our existing defenses would stop or contain an attack. We should confirm the vulnerable component is reachable by untrust input in our environment.
PoC: gha-lab-d14c91f1bb
Security-research lab: reproduction of CVE-2025-58371 (GitHub Actions command injection via PR title in Discord PR Notifier), snapshot of RooCodeInc/Roo-Code @ 08a825f9bb0086a88cff5a79b9af4731bba7d076
PoC: thymeleaf-check
Offline checker for Thymeleaf CVE-2026-40477 / CVE-2026-41901 — tells you which of the two CVSS 9.0 SSTI flaws you are exposed to, and whether your version line has a fix at all (3.0.x: it does not)
PoC: CVE-2024-36058
CVE-2024-36058 — Authenticated Time-Based Blind SQL Injection in Koha Library Software < 22.05.22 (opac-sendbasket.pl). Advisory + PoC by Hacklantic.
PoC: CVE-2024-36057
CVE-2024-36057 — Authenticated OS Command Injection in Koha Library Software < 22.05.22 (upload-cover-image.pl). Advisory + PoC by Hacklantic.
PoC: gha-lab-aa1cbc9bcf
Authorized security-research reproduction of CVE-2025-54594 (GHSA-588g-38p4-gr6x): privileged issue_comment-triggered canary release workflow checking out untrusted fork code and running its npm scripts with GITHUB_TOKEN/NPM_TOKEN in env. Snapshot of callstackincubator/react-native-bottom-tabs @ d765b1f695762490327dcb8f6a2f17542cf0abdb.
PoC: CVE-2026-82329-poc
CVE-2026-82329 Poc
PoC: CVE-2025-34158-CVE-2020-5741
CVE-2025-34158, CVE-2020-5741 - Draft or TODO
PoC: gha-lab-ba981941f0
Security-research lab reproducing CVE-2025-54430 (GHSA-wrg3-xqw8-m85p): secrets exfiltration via issue_comment-triggered Benchmark Bot in dedupeio/dedupe. Snapshot of dedupeio/dedupe@54ecfe77d41390da66899596834a2bde3712c966.
PoC: gha-lab-f894926966
Authorized security-research reproduction lab for CVE-2025-54415 (GHSA-g5hx-xv45-9whg): astronomer/dag-factory snapshot at 464c75a — pull_request_target head-SHA checkout executes attacker-controlled hatch scripts in base-repo context
PoC: gha-lab-6926364d94
Security research lab reproducing CVE-2025-53546 (GHSA-h87r-5w74-qfm4): pull_request_target arbitrary code execution in RSSNext/Folo's auto-fix lint workflow — authorized, isolated reproduction
PoC: CVE-2025-8518
CVE-2025-8518 - Draft or TODO
PoC: gha-lab-3b0a828a69
Security-research lab reproducing CVE-2025-53104 (GHSA-432r-9455-7f9x): command injection in discussion-to-slack.yml of gluestack/gluestack-ui
PoC: gha-lab-e8902eccd3
Security research lab: reproduction of CVE-2025-52467 (pgai pull_request_target workflow code execution / GITHUB_TOKEN exfiltration) — snapshot of timescale/pgai
PoC: tomcatfileread
CVE-2020-1938 (Ghostcat) Tomcat AJP file read/file include PoC with python3 port
PoC: CVE-Chamilo-LMS
CVE-2026-61578, CVE-2026-61582, CVE-2026-61583, CVE-2026-61584, CVE-2026-61585, CVE-2026-61587, CVE-2026-61600, CVE-2026-61601, CVE-2026-61602, CVE-2026-70647, CVE-2026-70648 - Draft or TODO
PoC: gha-lab-2f775f277c
Authorized lab reproduction of CVE-2025-47928 (spotipy-dev/spotipy pull_request_target secrets exfiltration) — snapshot at vulnerable commit 4f5759d
PoC: CVE-2026-31787
Linux kernel double free in Xen privcmd driver
PoC: gha-lab-fb6df3d456
Authorized security-research lab reproducing CVE-2025-46820 (GHSA-cwj7-6v67-2cm4): GITHUB_TOKEN persisted into publicly downloadable CI artifacts in phpgt/Dom. Snapshot of phpgt/Dom @ b73d7e8.
PoC: CVE-2026-20212
CVE-2026-20212 - Draft or TODO
PoC: CVE-2026-56718
AJCloud AJY IPC Firmware Path Traversal via jdbhttpd
PoC: psa-2026-00043-recovery
Recovery notes for proxmox advisory ID: PSA-2026-00043-1 (CVE-2023-54391)
PoC: gha-lab-ba8e0c4217
Authorized security-research lab: reproduction of CVE-2024-42370 / GHSA-4hq2-rpgc-r8r7 (env injection in docs-preview.yml) — snapshot of litestar-org/litestar@18d84d84
PoC: CVE-2026-65643-PoC-Toolkit
🧰 CVE-2026-65643 – cPanel Domain Parking RCE Toolkit (CVSS 8.7) | Red/Blue Team suite for unpatched cPanel & WHM 11.x (110,134,136,138). 2 tools: Full Exploit (reverse shell, webshell, persistence, root passwd, file R/W, mass scan, Tor), Blue Team PoC (detection, reporting, audit). w/Python. 🦾 Only Use Ethically, Stay Legal <3
PoC: CVE-2026-4813
PoC for CVE-2026-4813
PoC: cve-2026-75604
Research lab and exploit chain for CVE-2026-75604: path traversal in the Next.js incremental cache, to RCE on Windows.
PoC: CVE-2026-82329
CVE‑2026‑82329 is a critical authentication bypass in JFrog Artifactory (CVSS 9.8) allowing unauthenticated attackers to obtain full administrative privileges. Actively exploited in the wild. Affects self‑hosted versions before patches. PoC for authorized testing only.
PoC: CVE-2026-52810
CVE-2026-52810 - Draft or TODO
PoC: iOS26.6-CVE-2026-64788
CVE-2026-64788 PoC — IOGPUFamily Use-After-Free (iOS 26.6 / 23G71)
PoC: CVE-2026-80428
CVE-2026-80428 PoC
PoC: iOS26.6-CVE-2026-65343
CVE-2026-65343 PoC — AppleKeyStore OOB read → KASLR defeat (iOS 26.6 / 23G71)
PoC: CVE-2026-80428
CVE-2026-80428 PoC
PoC: gha-lab-b1fe4918c0
Authorized security-research lab: reproduction of CVE-2025-32958 (GHSA-8c7v-vccv-cx4q) — GITHUB_TOKEN leaked into workflow artifacts by Adept's remoteBuild.yml (snapshot of AdeptLanguage/Adept @ 6a64554)
PoC: CVE-2026-83548-SonicWall-SMA1000-Analysis
Vulnerability Analysis of CVE-2026-83548 affecting SonicWall SMA1000 security systems.
PoC: CVE-2024-21546
This repository contains security assessment tooling, detection templates, and an automated exploit toolkit for identifying and exploiting Unauthenticated Remote Code Execution (RCE) in applications utilizing the `UniSharp/laravel-filemanager` package (Versions `< 2.9.1`).
PoC: CVE-2026-78071
Stored XSS via Location Title in DPCalendar Free
PoC: CVE-2026-78070
SQL Injection via ORDER BY Shortcode in plg_content_dpcalendar — DPCalendar Free ≤ 10.11.2
PoC: CVE-2026-19949
CVE-2026-19949 - Draft or TODO
PoC: CVE-2026-59822
CVE-2026-59822 - Draft or TODO
PoC: struts2-tool
Struts2 S2-045/S2-046 CVE-2017-5638 detection & exploitation tool
PoC: gha-lab-becf103a54
Authorized security-research reproduction of CVE-2025-15617 (GHSA-6xqr-4q5g-xc7x): artipacked GITHUB_TOKEN leak in wazuh FIM Windows integration workflow artifacts
PoC: CVE-2025-9974
Proof of Concept code for the CVE-2025-9974 affecting Nokia Beacon routers.
PoC: tfo-connect-bypass
Bypassing connect()-based syscall rules using TCP Fast Open (CVE-2026-63828 PoC)
PoC: CVE-2026-38577-by-deepak-Anmol
CVE-2026-38577
PoC: gha-lab-23db52563c
Security-research lab: reproduction of CVE-2025-10894 (PR-title injection in GitHub Actions) — snapshot of nrwl/nx
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
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