PatchSiren cyber security CVE debrief

CVE-2026-47335 Canonical CVE debrief

A NULL pointer dereference vulnerability exists in Ubuntu Linux 6.8 within SAUCE patches handling AppArmor notifications. An unprivileged local user can trigger this flaw to cause a kernel panic, resulting in denial of service. The vulnerability was disclosed on 2026-05-28 with a CVSS 3.1 score of 5.5 (MEDIUM severity). The issue is tracked as CWE-476 (NULL Pointer Dereference). The vulnerability affects the Ubuntu kernel's AppArmor notification subsystem, specifically within SAUCE (Ubuntu-specific) patches. No known exploitation in the wild or ransomware campaign use has been reported. The fix is available via a kernel commit in the Ubuntu noble repository.

Vendor: Canonical
Product: Ubuntu Linux
CVSS: MEDIUM 5.5
CISA KEV: Not listed in stored evidence
Original CVE published: 2026-05-28
Original CVE updated: 2026-05-29
Advisory published: 2026-05-28
Advisory updated: 2026-05-29

Who should care

System administrators running Ubuntu 6.8 kernels with AppArmor enabled; security teams managing Ubuntu server and workstation fleets; kernel maintainers tracking Ubuntu-specific SAUCE patch security issues

Technical summary

The vulnerability resides in SAUCE patches for AppArmor notifications in Ubuntu Linux 6.8. A missing NULL check allows an unprivileged local attacker to dereference a NULL pointer, triggering a kernel panic. The attack requires local access but no user interaction. The CVSS 3.1 vector (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H) reflects high availability impact with no confidentiality or integrity impact. The fix involves proper NULL pointer validation in the AppArmor notification handling code path.

Defensive priority

medium

Recommended defensive actions

Apply the kernel patch from the Ubuntu noble repository commit referenced in the security advisory
Update to a fixed Ubuntu kernel version once released through standard distribution channels
Monitor Ubuntu Security Notices (USN) for official security update availability
Review systems running Ubuntu 6.8 kernel with AppArmor enabled for unexpected stability issues
Consider restricting unprivileged user access to AppArmor notification interfaces as a temporary mitigation where feasible

Evidence notes

Vulnerability description sourced from official CVE record and NVD entry. CVSS vector confirms local attack vector with low attack complexity. Weakness classification (CWE-476) provided by [email protected]. Vendor attribution to Ubuntu derived from Launchpad git repository reference and kernel source path.

Official resources

2026-05-28