CVE-2026-31431: Linux Kernel High-Severity Vulnerability

What is CVE-2026-31431?

In the Linux kernel, the following vulnerability has been resolved: crypto: algif_aead - Revert to operating out-of-place This mostly reverts commit 72548b093ee3 except for the copying of the associated data. There is no benefit in operating in-place in algif_aead since the source and destination come from different mappings. Get rid of all the complexity added for in-place operation and just copy the AD directly.

Technical Analysis

Weakness Classification

This vulnerability is classified as CWE-669.

Attack Vector Breakdown

• Attack Vector: Local
• Attack Complexity: Low
• Privileges Required: Low
• User Interaction: None
• Scope: Unchanged
• Confidentiality: High
• Integrity: High
• Availability: High

Impact Analysis

Exploitation requires local access to the target system, such as a local user session or a malicious file opened by a user. The attack complexity is low, meaning exploitation does not depend on specialized conditions or race windows. Successful exploitation can result in full confidentiality breach (complete data disclosure), complete integrity compromise (data modification or code execution), total availability loss (denial of service).

Exploitation Probability (EPSS): 2.2% chance of exploitation in the next 30 days (85th percentile). While the base probability may appear low, inclusion in CISA KEV confirms real-world exploitation is already occurring.

Exploit Availability

Public exploit code or proof-of-concept is available for CVE-2026-31431. This significantly increases the risk of exploitation, as attackers can use or adapt existing exploit code rather than developing their own. A public exploit reference has been identified. Organizations should treat this as an urgent patching priority.

Is CVE-2026-31431 being exploited?

Yes. CVE-2026-31431 is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, restricted to CVEs with confirmed active exploitation in the wild. CISA added this vulnerability on 2026-05-01. Inclusion in KEV triggers the patching mandate under BOD 22-01 for U.S. federal civilian agencies, with a remediation deadline of 2026-05-15. Additionally, public exploit code is available, which lowers the barrier for attackers.

How to fix CVE-2026-31431

Update the Linux kernel to the patched version via your distribution's package manager (apt, yum, dnf). A reboot is typically required after kernel updates. For environments where rebooting is not immediately possible, check if a livepatch/kpatch is available from your distribution vendor. Check the Linux Kernel CVEs page for the specific patch or update. CISA's Known Exploited Vulnerabilities catalog requires U.S. federal agencies to remediate this vulnerability by the due date shown below under Binding Operational Directive 22-01. Private organizations should treat KEV entries as priority-one patches because active exploitation has been confirmed in the wild.

Related Vulnerabilities

Other actively exploited vulnerabilities affecting Kernel or sharing the same weakness (CWE-669):

• CVE-2022-0492 (High 7.8) [same product] — A vulnerability was found in the Linux kernel’s cgroup_release_agent_write in…
• CVE-2018-14634 (High 7.8) [same product] — An integer overflow flaw was found in the Linux kernel's create_elf_tables()…
• CVE-2021-22555 (Unknown N/A) [same product] — Linux Kernel contains a heap out-of-bounds write vulnerability that could…
• CVE-2025-38352 (High 7.4) [same product] — In the Linux kernel, the following vulnerability has been…
• CVE-2023-0386 (Unknown N/A) [same product] — Linux Kernel contains an improper ownership management vulnerability, where…

Frequently asked questions

Is CVE-2026-31431 critical?

CVE-2026-31431 has a CVSS 3.1 base score of 7.8 — High severity. It should be treated as a priority patch, especially given the active exploitation confirmed by CISA. The availability of public exploit code further increases the urgency.

Is CVE-2026-31431 being actively exploited?

Yes — CISA added CVE-2026-31431 to the Known Exploited Vulnerabilities catalog on 2026-05-01. Inclusion in KEV means CISA has confirmed in-the-wild exploitation. Public exploit code has also been identified, making exploitation accessible to a broader range of threat actors.

How do I patch CVE-2026-31431?

Apply the security update from Linux for Kernel. Federal agencies must remediate by 2026-05-15 under BOD 22-01. Refer to the Linux Kernel CVEs for the official patch.

What type of vulnerability is CVE-2026-31431?

CVE-2026-31431 is classified under CWE-669.

What is the CVSS score for CVE-2026-31431?

CVE-2026-31431 has a CVSS 3.1 base score of 7.8, classifying it as High severity. The attack vector is Local, attack complexity is Low, and non-zero privileges are required.