Full Report
AL26-009 - Vulnerability Affecting Linux - CVE-2026-31431
Analysis Summary
# Vulnerability: Linux Kernel Incorrect Resource Transfer (Privilege Escalation)
## CVE Details
- **CVE ID:** CVE-2026-31431
- **CVSS Score:** Not explicitly listed (Severity: High/Critical indicated by "Significant"/"Prioritized")
- **CWE:** CWE-669: Incorrect Resource Transfer Between Spheres
## Affected Systems
- **Products:** Various Linux-based operating systems and distributions.
- **Versions:** Multiple kernel versions across major distributions.
- **Configurations:** Systems allowing local users, hosting containerized workloads, or executing untrusted code are at elevated risk.
## Vulnerability Description
CVE-2026-31431 is a flaw within the Linux kernel regarding how resources or privileges are transferred between security domains (spheres). This improper transfer allows an attacker to bypass isolation mechanisms. If successfully exploited, the flaw may allow for privilege escalation from a standard user to root. It is particularly dangerous when chained with a Remote Code Execution (RCE) vulnerability, as it allows an initial entry point to gain full administrative control of the system.
## Exploitation
- **Status:** Publicly reported; severity heightened when chained with RCE flaws.
- **Complexity:** Medium (Requires specific conditions/chaining for maximum impact).
- **Attack Vector:** Local (typically used for Privilege Escalation), but can be part of a Network attack chain.
## Impact
- **Confidentiality:** High (Potential root access leads to full data exposure).
- **Integrity:** High (Potential root access allows system modification).
- **Availability:** High (Potential to bypass isolation and disrupt services).
## Remediation
### Patches
- Organizations must check with their specific distribution maintainers for patches. Key vendors include:
- **Red Hat:** Enterprise Linux
- **Debian/Ubuntu**
- **SUSE:** SUSE Linux Enterprise / openSUSE
- **Community Distros:** Rocky Linux, AlmaLinux, Oracle Linux
- **Note:** Rebooting after kernel updates is mandatory to ensure the fix is active.
### Workarounds
- Restrict local and remote access to multi-tenant or shared environments.
- Isolate Internet-facing workloads using strict network segmentation.
- Review and minimize `sudo` and administrative role assignments.
## Detection
- **Indicators:** Monitor system, kernel, and authentication logs for unauthorized privilege escalation attempts or abnormal activity.
- **Methods:** Use `uname -r` to identify the running kernel version and cross-reference with vendor security advisories (note that some fixes are backported without changing the version string).
- **Tools:** Utilization of kernel-level security controls like **SELinux**, **AppArmor**, and **seccomp** to detect/prevent isolation bypasses.
## References
- **NVD:** hxxps[://]nvd.nist.gov/vuln/detail/CVE-2026-31431
- **CWE-669:** hxxps[://]cwe.mitre.org/data/definitions/669.html
- **Red Hat Advisory:** hxxps[://]access.redhat.com/security/cve/cve-2026-31431
- **Debian Tracker:** hxxps[://]security-tracker.debian.org/tracker/CVE-2026-31431
- **Ubuntu Advisory:** hxxps[://]ubuntu.com/security/CVE-2026-31431
- **SUSE CVE Search:** hxxps[://]www.suse.com/security/cve/CVE-2026-31431.html
- **Amazon Linux Security:** hxxps[://]explore.alas.aws.amazon.com/CVE-2026-31431.html
- **Mailing List:** hxxps[://]www.openwall.com/lists/oss-security/