CVE-2026-52936: crypto: jitterentropy - replace long-held spinlock with mutex

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-24 · updated 2026-10-30

Description

In the Linux kernel, the following vulnerability has been resolved: crypto: jitterentropy - replace long-held spinlock with mutex jent_kcapi_random() serializes the shared jitterentropy state, but it currently holds a spinlock across the jent_read_entropy() call. That path performs expensive jitter collection and SHA3 conditioning, so parallel readers can trigger stalls as contending waiters spin for the same lock. To prevent non-preemptible lock hold, replace rng->jent_lock with a mutex so contended readers sleep instead of spinning on a shared lock held across expensive entropy generation.

Affected products

Linux kernel: from 4.2 before 6.6.141; from 6.7 before 6.12.91; from 6.13 before 6.18.33; from 6.19 before 7.0.10 — fixed in 6.6.141, 6.12.91, 6.18.33, 7.0.10
Linux: 4.2 — fixed in 7.1

How to fix

Upgrade to a fixed version: Linux kernel 6.6.141, 6.12.91, 6.18.33, 7.0.10; Linux 7.1. Check the vendor advisory for mitigations.

References

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