CVE-2026-88899: knowns-dev knowns

knowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory Header

CVSS 9.3 CriticalCriticalEPSS 0.0081 · 57th percentile

Critical, because:

CVSS score 9.3: 9.0 or more.

Published by the CVE Program (CNA: VulnCheck) at 10 Sept 2026, 15:28 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
knowns-dev	knowns pkg:npm/knowns	affected before 0.31.0 semver unaffected 0.31.0 semver Other versions: unaffected

Identifiers

CVE-2026-88899

CNA

VulnCheck

Weakness (CWE)

CWE-73

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
9.3	Critical	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	CNA (VulnCheck)Used for this record
9.8	Critical	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0081, the 57th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 10 Sept 2026. New records show when each source confirmed them.

Sources

References from the CNA

github.com/knowns-dev/knowns/security/advisories/GHSA-9h2q-r9fh-f98w vendor-advisory
github.com/knowns-dev/knowns/blob/v0.30.0/internal/server/server.go#L1283-L1296 technical-description
github.com/knowns-dev/knowns/commit/37db0561b37b48b8bd035a417d7f1da6258ae657 patch
github.com/knowns-dev/knowns/releases/tag/v0.31.0 release-notes
www.vulncheck.com/advisories/knowns-before-0.31.0-external-control-of-agent-working-directory-via-x-opencode-directory-header third-party-advisory

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.