Authentication Bypass in github.com/coder/coder/v2 (CVE-2026-55076)
Summary
Authentication bypass in github.com/coder/coder/v2 (CVE-2026-55076). Confidential information can be exposed externally. Exploitable via email_verified. Mitigation: upgrade to 2.29.17 or later.
Original description
The description as published by the source.
Summary
Coder's OIDC callback checked email_verified with a direct Go bool type assertion. When an IdP returned the claim as a non-boolean (for example the string "false") or omitted it, the assertion failed open and the email was treated as verified. Combined with an unconditional email-based account fallback, this enabled account takeover.
Impact
An attacker who registered a victim's email at a compatible IdP without verifying it could log in via OIDC and be matched to the victim's existing Coder account, receiving a session for that account. No prior authentication to Coder was required and the result was full account takeover.
Patches
The fix coerces email_verified across bool, string and numeric types (fail-closed) and blocks the email fallback when the matched user already has a different linked IdP subject.
The fix was backported to all supported release lines:
| Release line | Patched version |
|---|---|
| 2.34 | v2.34.2 |
| 2.33 | v2.33.8 |
| 2.32 | v2.32.7 |
| 2.29 (ESR) | v2.29.17 |
Workarounds
Ensure the IdP returns email_verified as a native JSON boolean. The email-fallback linking issue has no configuration workaround; upgrading is required.
Resources
- Fix: #25712, #25713
Credits
Coder would like t…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-55076 has been found in github.com/coder/coder/v2.
Attackers can target a specific entry point like email_verified over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.4/10.
What to do: upgrade github.com/coder/coder/v2 to 2.29.17 or later.
If unsure, ask your IT team or search "github.com/coder/coder/v2 CVE-2026-55076" on the vendor's site.
CVE-2026-55076 (github.com/coder/coder/v2) — CWE-287 / CVSS v3 7.4
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: email_verified / bool
Patched: 2.29.17 — apply immediately
Workaround: Ensure the IdP returns email_verified as a native JSON boolean.
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Authentication bypass (CWE-287) exists in github.com/coder/coder/v2. Attackers reach the vulnerable code path via email_verified without authentication.
Check the vendor advisory for the affected versions of github.com/coder/coder/v2. Attack surface: email_verified / bool.
Severity: High (CVSS 7.4/10). Confidential information can be exposed externally.
Update to 2.29.17.
Workaround: Ensure the IdP returns email_verified as a native JSON boolean.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'github.com/coder/coder/v2' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'github.com/coder/coder/v2' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
github.com/coder/coder/v2を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply temporary workaround mitigate
Ensure the IdP returns `email_verified` as a native JSON boolean.パッチが適用されるまでの応急処置として、Ensure the IdP returns
email_verifiedas a native JSON boolean. を実施。回避策の副作用 (機能低下) を確認した上で。 -
3Apply patch patch
Upgrade github.com/coder/coder/v2 to 2.29.17ステージング環境で 2.29.17 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
4Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。