CVE-2026-88899CWE-73

CVE-2026-88899

Critical · published September 10, 2026

CVSS v3.1
9.8
EPSS
1%
Percentile
56.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
9.8 · CRITICAL
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
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
EPSS
0.00809 · 56.4th percentile
Weakness
CWE-73 · External Control of File Name or Path
Published
2026-09-10T20:18Z
References (5)
https://github.com/knowns-dev/knowns/blob/v0.30.0/internal/server/server.go#L1283-L1296 · [email protected]https://github.com/knowns-dev/knowns/commit/37db0561b37b48b8bd035a417d7f1da6258ae657 · [email protected]https://github.com/knowns-dev/knowns/releases/tag/v0.31.0 · [email protected]https://github.com/knowns-dev/knowns/security/advisories/GHSA-9h2q-r9fh-f98w · [email protected]https://www.vulncheck.com/advisories/knowns-before-0.31.0-external-control-of-agent-working-directory-via-x-opencode-directory-header · [email protected]
EPSS history
Timeline
  • 12 SEP 03:22Z
    EPSS moved — → 0%
    epss
  • 10 SEP 15:28Z
    knowns before 0.31.0 External Control of Agent Working Directory via x-opencode-directory Header
    cvelistv5