CVE-2026-45927

Summary

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.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/7752d36343862323bbeea4ce3adf0ec2ed86e122
• https://git.kernel.org/stable/c/f415e114b58fe02c41191e47f24bdabb438daf72
• https://git.kernel.org/stable/c/a2c86aa621c22f2a7e26c654f936d65cfff0aa91

• ←Previous
• Next→