CVE-2025-21964VulnerabilityPublished 26 May 2025Updated 11 Oct 2026

SUSE · security update for kernel

Affects SUSESource GCVE Database

Not known to be exploited : upgrade to 9.6 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

Severity

Medium

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

EPSS: 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 9.6

Exploitation evidence

Disclosed: evidence found.
CVE published 26 May 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 2026-10-25.

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 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

Upgrade redhat/kernel to 9.6.

Affected software

Product	Affected	Fixed in
Red Hatredhat/kernel`pkg:rpm/redhat/kernel`Other threats	Affected >=9 <9.6 =9.6 =9.8	Fixed in 9.6

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A security update patch is available from Red Hat and should be applied promptly. The system must be rebooted after applying the update for the fix to take effect. Refer to Red Hat's official advisory (RHSA-2025:8142) and update instructions at https://access.redhat.com/articles/11258 for detailed remediation steps.

Description

A security update addresses an integer overflow vulnerability in the Linux kernel's CIFS module related to processing the acregmax mount option (CVE-2025-21964). This vulnerability affects the kernel packages used in Red Hat Enterprise Linux 9 and related distributions. The issue has been rated as moderate severity by Red Hat Product Security. A patch is available and should be applied, followed by a system reboot to ensure the update takes effect.

Impact

The vulnerability could allow an attacker to cause an integer overflow while processing the acregmax mount option in the CIFS kernel module, potentially leading to unexpected behavior or security issues in the kernel. Red Hat rates the impact as moderate. There are no known exploits in the wild at this time.

Summary

CVE-2025-21964 is an integer overflow vulnerability in the Linux kernel's CIFS module that occurs while processing the acregmax mount option. This flaw could potentially lead to incorrect handling of mount options, impacting the kernel's stability or security. The vulnerability affects Red Hat Enterprise Linux 9 and related kernel packages. Red Hat has released a security update to fix this issue, and the update requires a system reboot. The vulnerability is tracked under CWE-190 (Integer Overflow or Wraparound).

CWE-190Integer Overflow or Wraparound (opens in a new tab)
Base weaknessLikelihood of exploit: Medium
The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.
Requirements
Ensure that all protocols are strictly defined, such that all out-of-bounds behavior can be identified simply, and require strict conformance to the protocol.
Requirements · Language Selection
Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.3 (opens in a new tab)
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
Attack patterns
Forced Integer Overflow (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 11 Oct 2026, 22:15 UTC

WeaknessesCWE-190

Technical details

References

Community reviews

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