XSS in Coder

CVE-2026-55437

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2, 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. Exploitation requires a victim to view attacker-controlled agent logs in the dashboard. The fix in versions 2.29.17, 2.32.7, 2.33.8, and 2.34.2 enables `escapeXML: true` so HTML metacharacters are escaped before DOM insertion. No known workarounds are available.

Vulnerability class: XSS (Cross-Site Scripting)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.003 (22.5th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 22.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-55437: held from 0.003 to 0.003.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

  • Coder — versions >= 2.34.0, < 2.34.2, >= 2.33.0, < 2.33.8, >= 2.30.0, < 2.32.7

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-55437?
CVE-2026-55437 is a medium-severity vulnerability in Coder, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2026-07-08.
How severe is CVE-2026-55437?
Medium severity. CVSS v3 base score is 5.4 out of 10.