---
id: CVE-2026-52936
title: 'crypto: jitterentropy - replace long-held spinlock with mutex'
summary: |-
  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 t…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 <
    21de77d06f6b540e870e64ef5ff56be4eb8ba08f
  - >-
    Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 <
    18216b8ab6904753eaf31baf453cb02ecd202ba4
  - >-
    Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 <
    4c03e6eb98443dc4d6d422a9780034a5b75376b4
  - >-
    Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 <
    ff734dbd9e2432601a6dcd167cfb0bf8a36d1880
  - >-
    Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 <
    ec427dc5286da1ed08f2d510e2147a7581b0cb02
  - >-
    Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 <
    01d798e9feb30212952d4e992801ba6bd6a82351
  - Linux 4.2
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T16:14:26.080799Z'
published: '2026-06-24'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T16:23:50.257Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-52936'
references:
  - url: 'https://git.kernel.org/stable/c/21de77d06f6b540e870e64ef5ff56be4eb8ba08f'
  - url: 'https://git.kernel.org/stable/c/18216b8ab6904753eaf31baf453cb02ecd202ba4'
  - url: 'https://git.kernel.org/stable/c/4c03e6eb98443dc4d6d422a9780034a5b75376b4'
  - url: 'https://git.kernel.org/stable/c/ff734dbd9e2432601a6dcd167cfb0bf8a36d1880'
  - url: 'https://git.kernel.org/stable/c/ec427dc5286da1ed08f2d510e2147a7581b0cb02'
  - url: 'https://git.kernel.org/stable/c/01d798e9feb30212952d4e992801ba6bd6a82351'
tags:
  - cve.org
epss: 0.00114
epssPercentile: 0.01505
ingestedAt: '2026-11-05T15:02:32.339Z'
---

## Overview

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

- `Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 < 21de77d06f6b540e870e64ef5ff56be4eb8ba08f`
- `Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 < 18216b8ab6904753eaf31baf453cb02ecd202ba4`
- `Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 < 4c03e6eb98443dc4d6d422a9780034a5b75376b4`
- `Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 < ff734dbd9e2432601a6dcd167cfb0bf8a36d1880`
- `Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 < ec427dc5286da1ed08f2d510e2147a7581b0cb02`
- `Linux >= bb5530e4082446aac3a3d69780cd4dbfa4520013 < 01d798e9feb30212952d4e992801ba6bd6a82351`
- `Linux 4.2`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.