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CVE-2025-39745

20
FAUCET Score

CVE-2025-39745 addresses a bug in the Linux kernel's rcutorture test suite, specifically affecting kernels built with CONFIG_PREEMPT_RT=y (Real-Time Linux). The vulnerability caused a kernel "splat" (a type of warning or crash) during testing due to an incorrect check for disabled Bottom Halves (BH) in RT kernels. This vulnerability is rated Medium with a CVSS score of 5.5 (AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H), indicating it requires local access and has low attack complexity, but can lead to a denial of service. The fix involves using softirq_count() instead of preempt_count() to accurately determine if BH is disabled in RT environments. Currently, there is no evidence of active exploitation, and no public exploit code (Metasploit, Nuclei, ExploitDB) is available. Community discussion and media coverage are minimal, suggesting low awareness and no immediate threat from this specific issue.

Impacted Technologies

VendorProductVersion(s)CPE
< 6.15.11CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
>= 6.16, < 6.16.2CPE matchmatch criteria
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.5MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.14%
Probability of exploitation in next 30 days
EPSS Percentile
4.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0014 is in the 25th percentile among its peer group of 15,940 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Patches (5)

redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 10Fixed in: kernel
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: kernel-rt
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: kernel
redhatvendor investigatingvia redhat_api
Product: Red Hat Enterprise Linux 9Fixed in: kernel-rt

Vendor Advisories (2)

redhatCVE-2025-39745Low

kernel: Linux kernel: Denial of Service in rcutorture due to incorrect preempt_count handling

Sep 11, 2025
microsoft2025-Sep/CVE-2025-39745Moderate

rcutorture: Fix rcutorture_one_extend_check() splat in RT kernels

Sep 9, 2025

References

git.kernel.org / stable/c/69c5ae0f441c2d72e8f48dc1e08464c172360c4c
Patch
git.kernel.org / stable/c/8d71351d88e478d3c4e945e3218e97ec677fd807
Patch
git.kernel.org / stable/c/a85550267247cdf5e7499be00ea8e388ab014e50
Patch