Full Report
Ubuntu security advisory (AV26-367)
Analysis Summary
# Vulnerability: Linux Kernel Vulnerabilities in Ubuntu Distributions (AV26-367)
## CVE Details
*Note: The primary advisory (AV26-367) serves as a roll-up notification for multiple Linux Kernel vulnerabilities addressed between April 13 and 19, 2026.*
- **CVE ID:** Multiple (Refer to Ubuntu Security Notices for specific identifiers)
- **CVSS Score:** Varies by specific CVE (Typically ranging from Medium to High/Critical for Kernel flaws)
- **CWE:** Commonly includes CWE-119 (Memory Corruption), CWE-416 (Use After Free), and CWE-264 (Permissions/Privilege Escalation)
## Affected Systems
- **Products:** Ubuntu Linux OS
- **Versions:**
- Ubuntu 14.04 LTS (ESM)
- Ubuntu 16.04 LTS (ESM)
- Ubuntu 18.04 LTS (ESM)
- Ubuntu 20.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 24.04 LTS
- Ubuntu 25.10
- **Configurations:** Systems running generic, low-latency, or cloud-optimized Linux kernels.
## Vulnerability Description
This advisory covers a suite of security updates for the Linux kernel. Technical flaws typically addressed in these windows include:
1. **Memory Management Errors:** Use-after-free or double-free vulnerabilities in the networking stack or filesystem drivers.
2. **Privilege Escalation:** Flaws in system calls (syscalls) or ioctl interfaces that allow a local user to gain root privileges.
3. **Denial of Service (DoS):** Null pointer dereferences or infinite loops that can be triggered to crash the host system.
## Exploitation
- **Status:** Dependent on specific CVE; typically, these involve PoC availability shortly after disclosure.
- **Complexity:** Low to Medium.
- **Attack Vector:** Primarily Local (Local Privilege Escalation), but some flaws in the networking stack may be triggerable via Adjacent or Network vectors.
## Impact
- **Confidentiality:** High (Potential for unauthorized data access via kernel memory leaks)
- **Integrity:** High (Potential for unauthorized modification of system files)
- **Availability:** High (Potential for system crashes/kernel panics)
## Remediation
### Patches
Users should update their package lists and upgrade the `linux-image` packages to the latest versions provided in the official Ubuntu repositories.
Specific commands:
`sudo apt-get update && sudo apt-get dist-upgrade`
**Required Versioning:** Users should verify their kernel version against the specific [Ubuntu Security Notices](https://ubuntu[.]com/security/notices) published between April 13–19, 2026.
### Workarounds
- No universal workaround; however, restricting access to unprivileged user namespaces and limiting access to compilers on production systems can reduce the risk of exploitation for many kernel-level flaws.
## Detection
- **Indicators of Compromise:** Unexpected system reboots, unusual kernel oops/panics in `/var/log/syslog`, or unauthorized entries in `/etc/shadow`.
- **Detection methods and tools:** Use `unhide`, `chkrootkit`, or `rkhunter` to check for anomalies resulting from kernel-level persistence.
## References
- Ubuntu Security Notices: hxxps://ubuntu[.]com/security/notices
- Canadian Centre for Cyber Security Advisory: hxxps://www[.]cyber[.]gc[.]ca/en/alerts-advisories/ubuntu-security-advisory-av26-367