CVE-2026-98590

/// Technical 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).

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References