{"id":"CVE-2026-55430","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-55430","generatedAt":"2026-10-28T00:17:02.131Z","title":"Coder allows organizations to provision remote development environments via Terraform.","description":"Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, the workspace app proxy resolves the target app from `httpapi.RequestHost()` which prefers the `X-Forwarded-Host` header over the real `Host` header. No middleware strips `X-Forwarded-Host` before routing and the header is not browser-forbidden so client-side JavaScript can set it on `fetch()` calls. Practical exploitation requires subdomain app routing (wildcard hostname) enabled, a victim who visits the attacker's shared app and a deployment whose upstream proxy does not strip `X-Forwarded-Host`. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 trusts `X-Forwarded-Host` only from configured trusted proxies and otherwise resolves the routing host from the verified request host. As a workaround, place an upstream reverse proxy that strips or overwrites `X-Forwarded-Host` on untrusted requests.","published":"2026-07-08T01:16:27.000Z","lastModified":"2026-07-08T19:43:15.000Z","status":"Analyzed","sourceIdentifier":"security-advisories@github.com","cvss":{"version":"3.1","score":6.8,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:N/A:N"},"cwe":["CWE-345","CWE-441"],"affected":["coder/coder"],"epss":{"score":0.00208,"percentile":0.10844,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/coder/coder/pull/26204","tags":["Issue Tracking","Patch"],"source":"security-advisories@github.com"},{"url":"https://github.com/coder/coder/releases/tag/v2.29.17","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/coder/coder/releases/tag/v2.32.7","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/coder/coder/releases/tag/v2.33.8","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/coder/coder/releases/tag/v2.34.2","tags":["Release Notes"],"source":"security-advisories@github.com"},{"url":"https://github.com/coder/coder/security/advisories/GHSA-5g4w-3vw9-478w","tags":["Patch","Vendor Advisory"],"source":"security-advisories@github.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-55430","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}