CVE-2026-88899: knowns · External Control of File Name or Path
Affects knowns-dev knownsSource CVE Database V5
Not known to be exploited · CVSS 9.3 Critical.
Data as of 10/25/2026, 16:58:58 UTC
- EPSS
- 0.8% chance of exploitation in 30 days – higher than 56% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 10 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wild: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| knowns-devknowns | Affected
| Fixed in
|
GitHubknowns-dev/knownspkg:github/knowns-dev/knownsOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
No explicit patch or remediation information is provided in the input data. Until a fix is available, restrict access to the /api/opencode endpoint and monitor for suspicious requests involving the x-opencode-directory header.
Description
knowns versions before 0.31.0 contain a vulnerability in the /api/opencode proxy endpoint where the x-opencode-directory request header is not properly validated. This allows remote attackers to specify arbitrary directory paths, potentially enabling file operations outside the intended project root on the host system. The vulnerability has a critical severity with a CVSS 4.0 score of 9.3.
Impact
An attacker can remotely execute file operations outside the intended project root directory on the host system by supplying arbitrary directory paths in the x-opencode-directory header. This can lead to unauthorized access, modification, or deletion of files, potentially compromising system integrity and confidentiality.
References
- github.com/knowns-dev/knowns/security/advisories/GHSA-9h2q-r9fh-f98w (opens in a new tab)
- github.com/knowns-dev/knowns/blob/v0.30.0/internal/server/server.go (opens in a new tab)
- github.com/knowns-dev/knowns/commit/37db0561b37b48b8bd035a417d7f1da6258ae657 (opens in a new tab)
- github.com/knowns-dev/knowns/releases/tag/v0.31.0 (opens in a new tab)
- vulncheck.com/advisories/knowns-before-0.31.0-external-control-of-agent-working-directory-via-x-opencode-directory-header (opens in a new tab)