CVE-2022-2652: Use of Externally-Controlled Format String in umlaeute/v4l2loopback

Severity: medium (CVSS 6.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2022-08-04 · updated 2026-06-17
Weakness: CWE-134

Description

Depending on the way the format strings in the card label are crafted it's possible to leak kernel stack memory. There is also the possibility for DoS due to the v4l2loopback kernel module crashing when providing the card label on request (reproduce e.g. with many %s modifiers in a row).

Affected products

umlaeute/v4l2loopback: before 0.12.6 — fixed in 0.12.6

How to fix

Upgrade to a fixed version: umlaeute/v4l2loopback 0.12.6. Check the vendor advisory for mitigations.

References

https://github.com/umlaeute/v4l2loopback/commit/e4cd225557486c420f6a34411f98c575effd43dd
https://huntr.dev/bounties/1b055da5-7a9e-4409-99d7-030280d242d5
https://github.com/umlaeute/v4l2loopback/commit/e4cd225557486c420f6a34411f98c575effd43dd
https://huntr.dev/bounties/1b055da5-7a9e-4409-99d7-030280d242d5

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