bpf: fix BPF_PROG_QUERY OOB write and cgroup backward compat (Linux Linux)

CVE-2026-74371
HIGH 7.8

At a glance

Source
NVD
EPSS
EPSS 0.18 % · percentile 7 ()
State
PUBLISHED
Published
Updated
Assigner
Linux
NVD status
Received

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: fix BPF_PROG_QUERY OOB write and cgroup backward compat BPF_PROG_QUERY writes back the 'query.revision' field unconditionally to userspace. If userspace passes a smaller 'bpf_attr' structure (e.g. 40 bytes, which was the layout before the addition of 'query.revision'), the kernel performs an out-of-bounds write. Fix this by propagating the user-provided attribute size 'uattr_size' down to the cgroup query handlers, and conditionally skipping writing the revision field to userspace when the provided buffer size is insufficient. query.revision in bpf_mprog_query is structurally identical to the cgroup case: a late tail field, written unconditionally. But the backward-compat hazard is not the same. The min-historical-size test is per command, and bpf_mprog_query only serves attach types that were born with revision in the struct: - tcx_prog_query -> BPF_TCX_INGRESS/EGRESS - netkit_prog_query -> BPF_NETKIT_PRIMARY/PEER tcx, netkit, the revision field, and bpf_mprog_query itself all landed in the same v6.6 merge window (053c8e1f235d added the mprog query API + revision; tcx in e420bed02507, netkit in 35dfaad7188c). There has never been a tcx/netkit BPF_PROG_QUERY userspace that doesn't know about revision. So for these commands the minimum legitimate struct already covers offset 56-64 — no old binary can be broken here. Contrast with cgroup: BPF_PROG_QUERY on cgroup attach types shipped in 2017; revision write-back was bolted on years later (120933984460). That path has a real population of pre-revision callers.

References

Scores

VersionScoreVectorScored by
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux
CVSS 3.1HIGH 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HNVD · 416baaa9-dc9f-4396-8d5f-8c081fb06d67 (Secondary)

European references

CERT-FR advisories

Affected products

ProductVersions
Linux · Linuxaffected 195814a38a6a712bcb44d3dfa5109e926e92bec4 < b78eb6efbf052d44a3a14726aa7c7d5aa2e544d7 ; affected 1209339844601ec1766f4ff430673fbcfe42bb51 < a7131340d0f95df9a541257dccab5d85e6bcdd2b ; affected 1209339844601ec1766f4ff430673fbcfe42bb51 < d3d630e8a7f3421bc2d204b87bdff35b4432a8e3 ; affected 1209339844601ec1766f4ff430673fbcfe42bb51 < 21c4b99b27f3f85b89256e81b3e997dec0a460d0
Linux · Linuxaffected 6.17 ; unaffected 0 < 6.17 ; unaffected 6.18.40 ≤ 6.18.* ; unaffected 7.1.5 ≤ 7.1.* ; unaffected 7.2 ≤ *

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD