Kernel mitigations — Copy Fail & Dirty Frag CVEs (May 2026)

GLF-OS enables a mitigation by default against three Local Privilege Escalation (LPE) vulnerabilities recently disclosed in the Linux kernel. No action is required for 99 %+ of gamers.

The vulnerabilities at a glance

CVE Nickname Kernel component Severity
CVE-2026-31431 Copy Fail AF_ALG crypto API (authencesn template) CVSS 7.8 (HIGH)
CVE-2026-43284 Dirty Frag (ESP) IPsec ESP esp4 / esp6 Important
CVE-2026-43500 Dirty Frag (rxrpc) RPC rxrpc (kAFS) Important

All three allow a local unprivileged user to gain root in seconds via publicly available exploit scripts.

What GLF-OS does for you

The glf.security.mitigations module (enabled by default on testing from May 2026) blacklists the vulnerable kernel modules. As a result, these modules no longer auto-load when an unprivileged program tries to open a socket that would normally trigger them (the typical exploit path).

Blocked module CVE covered Normal usage
algif_aead Copy Fail Rarely used from userspace (already patched at kernel level, blacklist is defense-in-depth)
esp4, esp6 Dirty Frag (ESP) Corporate IPsec VPN (strongSwan, libreswan, Cisco native IKEv2)
rxrpc Dirty Frag (rxrpc) Andrew File System (AFS) — academic use only

Impact on GLF-OS gamers — < 1 %

You use… Impact
Steam, Proton, Wine, Lutris, Heroic, Bottles ✅ None
EAC, BattlEye anti-cheats (Linux/Proton side) ✅ None
WireGuard, OpenVPN, Tailscale, ZeroTier ✅ None (they don't use kernel IPsec ESP)
ProtonVPN, Mullvad, NordVPN (standard clients) ✅ None
Corporate kernel xfrm IPsec VPN (strongSwan/libreswan/Cisco native IKEv2) ⚠️ Broken while the mitigation is active
AFS (in-kernel kAFS) ⚠️ Broken

If you fall in the last category, explicitly disable the mitigation:

# /etc/nixos/customConfig/default.nix
glf.security.mitigations.blacklistDirtyFrag = false;

Then:

glf-update

Verify the mitigation is active on your machine

grep -E "esp4|esp6|rxrpc|algif_aead" /etc/modprobe.d/nixos.conf

You should see four blacklist lines. If yes, you are protected.

lsmod | grep -E "esp[46]|rxrpc|algif_aead"

Expected output: empty (modules not loaded).

When this mitigation will be removed

GLF-OS will automatically lift the blacklist via glf.security.mitigations as soon as the distributed kernel includes all the fixes.

Sources