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.

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History

Wed, 27 May 2026 16:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362
CWE-824

Wed, 27 May 2026 14:15:00 +0000

Type Values Removed Values Added
Description 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.
Title bpf: Require frozen map for calculating map hash
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-27T12:17:46.284Z

Reserved: 2026-05-13T15:03:33.086Z

Link: CVE-2026-45927

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-27T14:17:08.583

Modified: 2026-05-27T14:48:03.013

Link: CVE-2026-45927

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-27T16:30:36Z

Weaknesses