Buffer overflow in FreeBSD
CVE-2026-45252
When a fusefs file system implements extended attributes, the kernel may send a FUSE_LISTXATTR message to the userspace daemon to retrieve the list of extended attributes for a given file. The FUSE protocol requires the daemon to return a packed list of NUL-terminated strings. The fusefs kernel module calls strlen() on this daemon-supplied buffer without first verifying that the entire list is NUL-terminated. If a malicious daemon sends a non-NUL-terminated list, the fusefs kernel module may read beyond the end of one heap-allocated buffer and potentially write beyond the end of a second buffer. A malicious daemon could disclose up to 253 bytes of kernel heap memory, or it could inject up to 250 attacker-controlled bytes into unallocated kernel heap space.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (35.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 36th percentile — 35.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.002
Affected products
- FreeBSD — versions 14.3, 15.0, 14.4-RELEASE
Weakness classification (CWE)
References
- security.freebsd.org/advisories/FreeBSD-SA-26:20.fusefs.asc (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-45252?
- CVE-2026-45252 is a medium-severity vulnerability in FreeBSD, classified under Heap-based Buffer Overflow. CVSS score: 5.5/10. Published 2026-05-21.
- How severe is CVE-2026-45252?
- Medium severity. CVSS v3 base score is 5.5 out of 10.