Vulnerability in FreeBSD
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. 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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.1 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H.
EPSS exploit prediction
EPSS: 0.001 (2.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 2nd percentile — 2.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000
Affected products
- FreeBSD — versions 14.3, 15.0, 14.4
Weakness classification (CWE)
References
- security.freebsd.org/advisories/FreeBSD-SA-26:42.unlinkat.asc (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-49421?
- CVE-2026-49421 is a high-severity vulnerability in FreeBSD, classified under Improper Check for Dropped Privileges. CVSS score: 7.1/10. Published 2026-08-19.
- How severe is CVE-2026-49421?
- High severity. CVSS v3 base score is 7.1 out of 10.