In the Linux kernel, the following vulnerability has been resolved: bpf: Fix bpf_sock context code generation Currently, the ctx access code reads the rx_queue_mapping field with either a 4-byte or 2-byte load. The rest of the bits in the register are marked known zero by the verifier. However, the emitted ctx access code places in the register on certain the special value (-1) using BPF_MOV_IMM64, which gets sign-extended to turn on all the bits in the register. By shifting this value right, the program ends up with a value at runtime above what the verifier assumes is possible. Fix this by ensuring the read value is as wide as the assumed size. Use MOV32 instructions instead of MOV64 instructions to keep the upper bits zero as assumed by the verifier. Also properly report the size of the destination variable (the bpf_sock field, 4 bytes) instead of the source (the socket field, 2 bytes).
Fix
Microsoft's update · Moderate
- Release Notes — azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 · build 6.6.159.1-1
From the 2026-Oct release note of Microsoft's Security Update Guide, revised 2026-10-30.
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 2
- StatusReceived → PublishedNVD modified 2026-10-19 09:22
- First seenunscoredNVD modified 2026-10-19 10:19
Affected (CPE criteria) 0
NVD has not attached CPE configurations yet.
References 8
- https://git.kernel.org/stable/c/4a41d064facc3330e176ecbbf5b0026ed18a5c69
- https://git.kernel.org/stable/c/4a4852376e3a2727ea40e61143d6d7c22bb6dfad
- https://git.kernel.org/stable/c/70288599d1754e157df8326239316dbdf08ea33c
- https://git.kernel.org/stable/c/84ebb991ae985149079ae9ab51b7e3ba25a9ff53
- https://git.kernel.org/stable/c/b3f37afc7fd7c52bc2114310aff1eb24c7cd4d73
- https://git.kernel.org/stable/c/d95dd5a6c6cd08d5ae466d3aed27b3cf59155a6c
- https://git.kernel.org/stable/c/e3ddcf4aeb342d4de2e5761c7042270d454752de
- https://git.kernel.org/stable/c/ea4dc96c902ccfa49dd3e4f23c443dab4a74b018