CVE-2026-88899

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

CRITICAL 9.3EPSS 0.8%

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.

Affected: knowns-dev · knowns
CVSS v4.0 VULNCHECK: 9.3 CRITICALCVSS: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
CVSS v3.1 VULNCHECK: 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.81% chance of exploitation in the next 30 days, 56th percentile
Published: 2026-09-10
Updated: 2026-09-11

Proof-of-concept exploits (1)

uziii2208/CVE-2026-888990★ · 2026-09-14

References

CVE Record
NVD entry

CVE-2026-88899

Proof-of-concept exploits (1)

References

Related