CVE-2026-49421
The kernel function that implements unlinkat(2) and funlinkat(2) validated the AT_RESOLVE_BENEATH flag but failed to pass it through to the underlying path lookup.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.09%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
The kernel function that implements unlinkat(2) and funlinkat(2) validated the AT_RESOLVE_BENEATH flag but failed to pass it through to the underlying path lookup. The flag was silently dropped, so path resolution was not actually restricted. A process that uses AT_RESOLVE_BENEATH with unlinkat(2) or funlinkat(2) to confine path resolution can in fact resolve paths above the starting directory. A caller relying on this flag for path containment may delete files outside the intended directory tree.
- CVSS 3.1
- 7.1 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H
- EPSS
- 0.09% probability · 1th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-273
- Affected
- freebsd/freebsd
- Source
- secteam@freebsd.org
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.