crypto: jitterentropy - replace long-held spinlock with mutex
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and Red Hat.
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 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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 4.2 and later | 6.1.191, 6.6.141, 6.12.91, 6.18.33, 7.0.10, 7.1 | Patch available | CNA |
- Linux VendorLinux Affected 4.2 and later Fixed in 6.1.191, 6.6.141, 6.12.91, 6.18.33, 7.0.10, 7.1 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 4.2 to before 6.6.141; 6.7 to before 6.12.91; 6.13 to before 6.18.33; 6.19 to before 7.0.10 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 4.2 to before 6.6.141; 6.7 to before 6.12.91; 6.13 to before 6.18.33; 6.19 to before 7.0.10 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.141, 6.12.91, 6.18.33, 7.0.10, 7.1
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-52936
- 2026-10-03 Alias added: GHSA-9hmp-j3gc-jm6j
- 2026-10-30 Fix available: Linux/Linux@21de77d06f6b540e870e64ef5ff56be4eb8ba08f, Linux/[email protected] · CNA
- 2026-10-30 1 new reference · CNA
- 2026-11-06 CISA SSVC decision points changed
References
Patch 5
- https://git.kernel.org/stable/c/18216b8ab6904753eaf31baf453cb02ecd202ba4
- https://git.kernel.org/stable/c/4c03e6eb98443dc4d6d422a9780034a5b75376b4
- https://git.kernel.org/stable/c/ff734dbd9e2432601a6dcd167cfb0bf8a36d1880
- https://git.kernel.org/stable/c/ec427dc5286da1ed08f2d510e2147a7581b0cb02
- https://git.kernel.org/stable/c/01d798e9feb30212952d4e992801ba6bd6a82351
More Linux Kernel vulnerabilities
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- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2026-52936 · CVE Program
- CVE-2026-52936 · NVD
- FIRST EPSS
- GHSA-9hmp-j3gc-jm6j · GitHub Advisory Database · CC BY 4.0
- CVE-2026-52936 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences