Vulnerability in Linux

CVE-2026-45927

In the Linux kernel, the following vulnerability has been resolved: bpf: Require frozen map for calculating map hash Currently, bpf_map_get_info_by_fd calculates and caches the hash of the map regardless of the map's frozen state. This leads to a TOCTOU bug where userspace can call BPF_OBJ_GET_INFO_BY_FD to cache the hash and then modify the map contents before freezing. Therefore, a trusted loader can be tricked into verifying the stale hash while loading the modified contents. Fix this by returning -EPERM if the map is not frozen when the hash is requested. This ensures the hash is only generated for the final, immutable state of the map.

Vulnerability class: TOCTOU (Time-of-Check to Time-of-Use)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.001 (1.1th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 1st percentile — 1.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-45927: held from 0.001 to 0.001.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: +0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-45927?
CVE-2026-45927 is a medium-severity vulnerability in Linux, classified under Time-of-check Time-of-use (TOCTOU) Race Condition. CVSS score: 4.7/10. Published 2026-05-27.
How severe is CVE-2026-45927?
Medium severity. CVSS v3 base score is 4.7 out of 10.