CVE-2026-53262

A flaw was found in the Linux kernel's pppol2tp module. This Use-After-Free (UAF) vulnerability arises from improper handling of session references within the pppol2tp_ioctl() function. A local attacker could exploit this by triggering a race condition during data copying, leading to the dereferencing of a stale session pointer. This could result in a system crash, causing a Denial of Service (DoS), or potentially allow for arbitrary code execution.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

To mitigate this issue, prevent the l2tp_ppp kernel module from loading automatically:

1. Create a configuration file in /etc/modprobe.d/ to disable loading of the module:

# echo "install l2tp_ppp /bin/true" > /etc/modprobe.d/l2tp_ppp.conf

2. If the module is currently loaded, unload it:

# modprobe -r l2tp_ppp

Warning: If the module is in active use by running processes, unloading will fail and a system reboot will be required to apply the configuration. Caveat: Disabling this module prevents the system from establishing or maintaining PPP over Layer 2 Tunneling Protocol (L2TP) connections.