CVE-2026-55437Medium· 5.4▾ SunlitCoder vulnerable to stored HTML injection via workspace agent logs in AgentLogLine component
▾ Sunlit zone — Low / medium · no exploitation signal
impact 29.7 · likelihood 0.1 · exploitation 0
Need a working PoC? Pro members can cast a request and our team develops one — it lands right here.
Exploit-prediction probability, daily snapshots since Jul 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.3%
0.3% → 0.3%
The AgentLogLine dashboard component instantiated ansi-to-html without escapeXML: true and inserted the result via dangerouslySetInnerHTML so HTML embedded in workspace agent log lines was rendered as live markup. Server-side sanitization did not neutralize HTML metacharacters.
Note: Exploitation requires a victim to view attacker-controlled agent logs in the dashboard.
A user who could run a workspace could emit arbitrary HTML into agent logs; when another user, including an administrator, viewed the workspace page, it rendered in their session. Content Security Policy blocked inline scripts but an attacker could still inject a meta refresh redirect, style rules for UI redressing or CSS-based exfiltration or external img beacons. This required workspace-owner access and a victim viewing the page.
The fix enables escapeXML: true so HTML metacharacters are escaped before DOM insertion.
The fix was backported to all supported release lines:
None.
Coder would like to thank Anthropic's Security Team (ANT-2026-22449) for independently disclosing this issue!
github.com/coder/coder/v2 >= 2.34.0, < 2.34.2github.com/coder/coder/v2 >= 2.33.0, < 2.33.8github.com/coder/coder/v2 >= 2.30.0, < 2.32.7github.com/coder/coder/v2 < 2.29.17Upgrade to a patched release:
github.com/coder/coder/v2 2.34.2github.com/coder/coder/v2 2.33.8github.com/coder/coder/v2 2.32.7github.com/coder/coder/v2 2.29.17Connected by shared product, vendor, weakness, or advisory.
CVE-2024-27918High· 8.2Coder's OIDC authentication allows email with partially matching domain to register
GHSA-8fxq-53rx-ph5fLow· 3.7Coder: Login endpoint user enumeration via timing-defense placeholder in password comparison
GHSA-h58c-xccx-75m3Low· 3.4Coder: Stored HTML injection via unescaped ApplicationName and LogoURL appearance settings
GHSA-qrwj-vh9x-gw5vHigh· 8.3Coder's workspace agent API insecure redirect handling allowed cross-agent file read and write
CVE-2026-55076High· 7.4Coder's OIDC email_verified type coercion bypass enables account takeover via unverified email linking
CVE-2026-55075High· 7.4Coder vulnerable to OIDC account takeover via email-based user matching and email_verified bypass