Linux Kernel: privilege escalation flaw under attack

What is affected

Linux Kernel is found on ordinary personal computers and phones, so this is not only a problem for companies. If you use it and have not updated since the fix was released, you are exposed.

Linux Kernel contains an incorrect resource transfer between spheres vulnerability that could allow for privilege escalation.

What an attacker can do

This is a privilege escalation flaw. It lets an attacker turn limited access into full administrator control. Attackers pair it with another flaw or a malicious file: once anything of theirs runs on the device, this bug lets it take over completely.

How it is reached

Needs access to the device or a file opened on it

Access the attacker needs

A basic user account

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. Update Linux Kernel now. Open the update or "About" screen, install whatever is offered and restart the app or device, because the fix is not active until you do.
2. Turn on automatic updates so the next fix arrives without you having to look for it.
3. If your device is too old to receive this update, stop using the affected app for anything sensitive and plan a replacement.

"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• lore.kernel.orglore.kernel.org/linux-cve-announce/2026042214-CVE-2026-31431-3d65@gregkh/
• xint.ioxint.io/blog/copy-fail-linux-distributions#the-fix-6
• git.kernel.orggit.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/about/

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on May 1, 2026, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by May 15, 2026, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 3.4% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 89% of all scored vulnerabilities.

Its CVSS severity score is 7.8 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

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.