CVE-2026-55437

### Summary 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. ### Impact 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. ### Patches The fix enables `escapeXML: true` so HTML metacharacters are escaped before DOM insertion. The fix was backported to all supported release lines: | Release line | Patched version | |---|---| | 2.34 | [v2.34.2](https://github.com/coder/coder/releases/tag/v2.34.2) | | 2.33 | [v2.33.8](https://github.com/coder/coder/releases/tag/v2.33.8) | | 2.32 | [v2.32.7](https://github.com/coder/coder/releases/tag/v2.32.7) | | 2.29 (ESR) | [v2.29.17](https://github.com/coder/coder/releases/tag/v2.29.17) | ### Workarounds None. ### Resources - Fix: #25808 ### Credits Coder would like to thank Anthropic's Security Team (ANT-2026-22449) for independently disclosing this issue!