CVE-2026-88899 json
knowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory Header
published 2mo ago modified 2mo ago also EUVD-2026-75579 , GHSA-9h2q-r9fh-f98w
Unreviewed: the maintainers' own advisory
Published by the maintainers on their GitHub repository knowns-dev/knowns. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.8%
- EPSS 0.8% chance of exploitation in 30 days, percentile 57%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- npm knowns 0.31.0
- knowns-dev knowns 0.31.0
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- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- 2mo ago
Exploit prediction
0.81% chance of exploitation in the next 30 days, higher than 57% of all scored CVEs (FIRST EPSS, 2026-11-11).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 9.3 | 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 |
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 9.3 | 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 |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| npm | knowns | <=0.30.0 |
0.31.0 |
Affected products
- knowns-dev knowns
Classification
- Weakness
-
- CWE-73 External Control of File Name or Path
References
-
github.com
/knowns-dev/knowns/commit/37db0561b37b48b8bd035a417d7f1da6258ae657
patch
-
github.com
/knowns-dev/knowns/security/advisories/GHSA-9h2q-r9fh-f98w
vendor-advisory, advisory
-
github.com
/knowns-dev/knowns/blob/v0.30.0/internal/server/server.go#L1283-L1296
technical-description
-
github.com
/knowns-dev/knowns/releases/tag/v0.31.0
release-notes
-
vulncheck.com
/advisories/knowns-before-0.31.0-external-control-of-agent-working-directory-via-x-opencode-directory-header
third-party-advisory
Sources
- CVE List CVE-2026-88899
- NVD CVE-2026-88899
- Maintainer advisory GHSA-9h2q-r9fh-f98w
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
The maintainers of knowns-dev/knowns published their own advisory on GitHub. Reviewed sources take precedence over it.