SB20261022167 - Unexpected Sign Extension in Linux kernel core

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Main Vulnerability Database SB20261022167

SB20261022167 - Unexpected Sign Extension in Linux kernel core

Published: October 22, 2026

Security Bulletin ID SB20261022167
CSH Severity
Low
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Local access
Highest impact Code execution

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Unexpected Sign Extension (CVE-ID: CVE-2026-98590)

CWE-ID: CWE-194 - Unexpected Sign Extension

CVSSv4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]


The vulnerability allows a local user to bypass BPF verifier assumptions about the range of runtime register values.

The vulnerability exists due to unexpected sign extension and incorrect destination-size accounting in bpf_sock context access code generation when processing access to the rx_queue_mapping field. A local user can execute a specially crafted BPF program that right-shifts the sign-extended value to produce a runtime value outside the bounds assumed by the verifier.


Remediation

Install update from vendor's website.

References