CVEvulnerability
CVE-2026-98590
- Status
- Received
- Published
- 2026-10-18
- Last modified
- 2026-10-19
- Assigner
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Description
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).
References
- https://git.kernel.org/stable/c/4a41d064facc3330e176ecbbf5b0026ed18a5c69 git.kernel.org
- https://git.kernel.org/stable/c/4a4852376e3a2727ea40e61143d6d7c22bb6dfad git.kernel.org
- https://git.kernel.org/stable/c/70288599d1754e157df8326239316dbdf08ea33c git.kernel.org
- https://git.kernel.org/stable/c/84ebb991ae985149079ae9ab51b7e3ba25a9ff53 git.kernel.org
- https://git.kernel.org/stable/c/b3f37afc7fd7c52bc2114310aff1eb24c7cd4d73 git.kernel.org
- https://git.kernel.org/stable/c/d95dd5a6c6cd08d5ae466d3aed27b3cf59155a6c git.kernel.org
- https://git.kernel.org/stable/c/e3ddcf4aeb342d4de2e5761c7042270d454752de git.kernel.org
- https://git.kernel.org/stable/c/ea4dc96c902ccfa49dd3e4f23c443dab4a74b018 git.kernel.org