CVE-2025-39841VulnerabilityPublished 10 Dec 2025Updated 30 Jun 2026

Red Hat Security Advisory: kernel-rt security update

Affects Linux kernelSource GCVE Database

Mentioned vulnerabilities

CVE-2025-39883

Not known to be exploited.

Data as of 26 Oct 2026, 17:16 UTC

Severity

Medium

Rated by Threat Radar · No CVSS score from NVD or the CNA

EPSS: 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Affected software

Product	Affected	Fixed in
Red Hat Product Security Red Hat	Affected Red Hat Red Hat Enterprise Linux Red Hat Enterprise Linux Real Time E4S (v.9.2) Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) src	Fixed in–

AI-suggested

Red Hat has released updated kernel-rt packages that fix these vulnerabilities. Users of Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions and Extended Life Cycle 9.2 should apply the security update as described in Red Hat advisory RHSA-2025:22995. A system reboot is required for the update to take effect. Patch status is confirmed as available via the vendor advisory. No additional mitigation steps are indicated.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements. Security Fix(es): * kernel: scsi: lpfc: Fix buffer free/clear order in deferred receive path (CVE-2025-39841) * kernel: mm/memory-failure: fix VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoison memory (CVE-2025-39883) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Impact

The vulnerabilities affect the kernel-rt packages used in Red Hat Enterprise Linux 9.2 variants, potentially causing improper memory handling and buffer management in kernel subsystems. This could lead to system instability or other unintended behavior. Red Hat rates the impact as moderate. There are no reports of active exploitation in the wild.

Summary

The Red Hat kernel-rt packages, which enable fine-tuning for real-time Linux systems, contain two security flaws. CVE-2025-39841 is a flaw in the SCSI lpfc driver related to the order of buffer free and clear operations in the deferred receive path. CVE-2025-39883 is a memory management issue where the kernel triggers a VM_BUG_ON_PAGE(PagePoisoned(page)) when unpoisoning memory, indicating improper handling of poisoned pages. Red Hat has issued a security advisory (RHSA-2025:22995) providing updated kernel-rt packages for Red Hat Enterprise Linux 9.2 variants that address these vulnerabilities. The advisory states a moderate security impact and requires a system reboot to apply the fixes. No CVSS scores are provided in the advisory, and no exploits are currently known in the wild.

CWE-416Use After Free (opens in a new tab)
Variant weaknessLikelihood of exploit: HighCWE Top 25 (2025): #7
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.
Architecture and Design · Language Selection
Choose a language that provides automatic memory management.
Implementation · Attack Surface Reduction
When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
V5.1.3 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

Loading reviews…

Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 25 Jun 2026, 22:19 UTC

WeaknessesCWE-416

Technical details

References

Community reviews

Related threats