The vulnerability in the algif_aead module is a high-severity Local Privilege Escalation (LPE) flaw known as "Copy Fail" (CVE-2026-31431). 
It affects almost all major Linux distributions that have used the affected kernel code since 2017.
    
The Core Flaw 
• Mechanism: A faulty in-place operation optimization introduced in 2017 allows page cache pages to be placed in a writable destination scatterlist without enforcement. 
• Exploitation: An unprivileged local attacker can chain socket operations with  to perform a controlled 4-byte write into the page cache of readable binaries (e.g.,  or ). 
• Impact: The in-memory corruption modifies a  or  binary, granting the attacker instant root privileges. Because the file on disk is never changed, it evades standard file integrity checks. 
• Severity: CVSS score of 7.8 (High)

How to Remediate 
The upstream Linux kernel community released a patch that reverts the 2017 optimization to ensure safe "out-of-place" operations. 

Solution 1:

1. Update Your Kernel: Immediately patch your Linux kernel to the latest version provided by your distribution and reboot the system. 
2. Apply Immediate Mitigations: If you cannot immediately patch, you can disable the  module to prevent exploitation: 

Solution 2:
If you are unable to apply a patch , delete the module and blacklist it to prevent it from loading.

# rm /lib/modules/$(uname -r )/kernel/crypto/algif_aead.ko
# echo "blacklist algif_aead" > /etc/modprobe.d/disable_algif_aead.conf
# lsmod | grep -i aead
# modprobe -r