CVE-2026-53262
Description
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.
Mitigation
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.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.8 | N/A | 7.8 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | Low | N/A | Low |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | High | N/A | High |
| Integrity Impact | High | N/A | High |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Resource Consumption (Memory); DoS: Resource Consumption (Other)
If an adversary can prevent a reference count from reaching zero, then resources might not be released when they are supposed to, thus causing resources to become scarce for future needs.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
If an adversary can cause a reference count to reach zero when the resource is still in use, then a resource might be released before it is supposed to be, possibly forcing an error that causes the product to crash or exit out of its current operation.
Frequently Asked Questions
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