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CVE-2026-88899
knowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory Header
Critical9.3EPSS 0.81%
- Published
- Updated
- Reserved
- Assigned by
- VulnCheck
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.
Timeline
ID reserved
By VulnCheck
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulnCheckCNA (assigner) | 4.0 | Critical9.3 | 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 |
| VulnCheckCNA (assigner) | 3.1 | Critical9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Deferred | 4.0 | Critical9.3 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.81% · top 43% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
Loading the EPSS history…
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.3.
Weakness
Affected products
- affected < 0.31.0
- unaffected 0.31.0
References (5)
- GitHub Security Advisory (GHSA-9h2q-r9fh-f98w) (opens in a new tab)vendor-advisory
- https://github.com/knowns-dev/knowns/blob/v0.30.0/internal/server/server.go#L1283-L1296 (opens in a new tab)technical-description
- https://github.com/knowns-dev/knowns/commit/37db0561b37b48b8bd035a417d7f1da6258ae657 (opens in a new tab)patch
- knowns v0.31.0 Release Notes (opens in a new tab)release-notes
- VulnCheck Advisory: knowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory Header (opens in a new tab)third-party-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-88899)Record last updated .