CVE-2026-88899: knowns · External Control of File Name or Path
Affects knownsSource CVE Database V5
Not known to be exploited · CVSS 9.3 Critical : upgrade to 0.31.0 as a priority.
Data as of 25 Oct 2026, 19:02 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.
- Patch
- Available – fixed in 0.31.0
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 wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
Upgrade knowns and knowns-dev/knowns to 0.31.0.
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
If you cannot patch yet, 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.
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)