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CVE-2026-98590

Unknown

Last modified

CVE-2026-98590 is a vulnerability of currently unknown severity. 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.

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).

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= c3c16f2ea6d20159903cf93afbb1155f3d8348d5, < e3ddcf4aeb342d4de2e5761c7042270d454752de; >= c3c16f2ea6d20159903cf93afbb1155f3d8348d5, < 4a41d064facc3330e176ecbbf5b0026ed18a5c69; >= c3c16f2ea6d20159903cf93afbb1155f3d8348d5, < 70288599d1754e157df8326239316dbdf08ea33c; >= c3c16f2ea6d20159903cf93afbb1155f3d8348d5, < ea4dc96c902ccfa49dd3e4f23c443dab4a74b018; >= c3c16f2ea6d20159903cf93afbb1155f3d8348d5, < b3f37afc7fd7c52bc2114310aff1eb24c7cd4d73; >= c3c16f2ea6d20159903cf93afbb1155f3d8348d5, < d95dd5a6c6cd08d5ae466d3aed27b3cf59155a6c; >= c3c16f2ea6d20159903cf93afbb1155f3d8348d5, < 84ebb991ae985149079ae9ab51b7e3ba25a9ff53; >= c3c16f2ea6d20159903cf93afbb1155f3d8348d5, < 4a4852376e3a2727ea40e61143d6d7c22bb6dfad
LinuxLinux5.8

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-98590?
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).
How severe is CVE-2026-98590?
Severity scoring for CVE-2026-98590 is pending analysis.
How do I fix CVE-2026-98590?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST