SB2026082130 - Ubuntu update for linux
Published: August 21, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 vulnerability.
1) Improper input validation (CVE-ID: CVE-2026-64531)
CWE-ID: CWE-20 - Improper input validation
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper handling of oversized nested action attributes in openvswitch flow action construction when processing user-supplied openvswitch nested action attributes. A local user can supply specially crafted nested CLONE or CT actions to cause a denial of service.
The issue occurs because a generated nested action attribute can be closed with a truncated nla_len, causing later dump or teardown operations to walk a structurally different action stream than the one that was validated.
Remediation
Install update from vendor's website.