CVE-2025-39745: Linux kernel · rcutorture: Fix rcutorture_one_extend_check() splat in RT kernels
Affects Linux kernelSource CVE Database V5
Not known to be exploited · fixed in a85550267247cdf5e7499be00ea8e388ab014e50 : update Linux kernel when convenient.
Data as of 5 Nov 2026, 21:48 UTC
Rated Low by Threat Radar's AI analysis · No CVSS score from NVD or the CNA
Thin evidence
One scorer or none- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Limited control over the software or limited information exposure
CISA SSVC assessment, 2026-11-05.
- Patch
- Available – fixed in a85550267247cdf5e7499be00ea8e388ab014e50, 69c5ae0f441c2d72e8f48dc1e08464c172360c4c, 8d71351d88e478d3c4e945e3218e97ec677fd807
Exploitation evidence
Disclosed: evidence found.
CVE published 11 Sep 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade Linux kernel to a85550267247cdf5e7499be00ea8e388ab014e50, 69c5ae0f441c2d72e8f48dc1e08464c172360c4c or 8d71351d88e478d3c4e945e3218e97ec677fd807.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix is available in the Linux kernel source code as identified by the provided commit hashes. Users running real-time kernels with CONFIG_PREEMPT_RT=y should update to a kernel version that includes these fixes to prevent the rcutorture_one_extend_check() crash. No additional mitigation steps are indicated.
Description
A vulnerability in the Linux kernel's rcutorture test suite for real-time (RT) kernels caused a kernel crash (splat) due to incorrect handling of softirq and bottom half (BH) disable counts. This was fixed by changing the check to use softirq_count() instead of relying on preempt_count() bits. The issue affected Linux kernel version 6.14.