CVE-2022-2503: Linux Kernel LoadPin bypass via dm-verity table reload

Vulnerability summary

CVE-2022-2503 is a medium (CVSS 6.9) vulnerability in linux kernel. EPSS estimates a 0.42% chance of exploitation in the next 30 days, higher than 36.3% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 12-08-2022
   PublishedVulnerability first disclosed.
2. 14-10-2026
   Last modifiedVulnerability information updated.

Description

Dm-verity is used for extending root-of-trust to root filesystems. LoadPin builds on this property to restrict module/firmware loads to just the trusted root filesystem. Device-mapper table reloads currently allow users with root privileges to switch out the target with an equivalent dm-linear target and bypass verification till reboot. This allows root to bypass LoadPin and can be used to load untrusted and unverified kernel modules and firmware, which implies arbitrary kernel execution and persistence for peripherals that do not verify firmware updates. We recommend upgrading past commit 4caae58406f8ceb741603eee460d79bacca9b1b5

• CWE-302Authentication Bypass by Assumed-Immutable DataThe authentication scheme or implementation uses key data elements that are assumed to be immutable, but can be controlled or modified by the attacker.
• CWE-287Improper AuthenticationWhen an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.