CVE-2026-88899
knowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory Header
- State
- Published
- Severity
- 9.3 Critical
- Published
- Sep 10, 2026
- Updated
- Sep 11, 2026
- Reserved
- Sep 10, 2026
Description
knowns versions before 0.31.0 fail to properly validate the x-opencode-directory request header in the /api/opencode proxy endpoint. Remote attackers can supply arbitrary directory paths to execute file operations outside the project root on the host system.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.3 Critical | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | VulnCheck |
Weaknesses
- CWE-73 External Control of File Name or Path
Affected Products
| Product | Versions |
|---|---|
knownsknowns-dev |
|
References
- GitHub Security Advisory (GHSA-9h2q-r9fh-f98w)vendor-advisory
- https://github.com/knowns-dev/knowns/blob/v0.30.0/internal/server/server.go#L1283-L1296technical-description
- https://github.com/knowns-dev/knowns/commit/37db0561b37b48b8bd035a417d7f1da6258ae657patch
- knowns v0.31.0 Release Notesrelease-notes
- VulnCheck Advisory: knowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory Headerthird-party-advisory
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.