VulnerabilityPublished 12 Sep 2025Updated 5 Nov 2026

CVE-2025-39795: Linux kernel · block: avoid possible overflow for chunk_sectors check in blk_stack_limits()

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in 418751910044649baa2b424ea31cce3fc4dcc253 : update Linux kernel when convenient.

Data as of 5 Nov 2026, 21:35 UTC

Severity

Unrated

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

Thin evidence

One scorer or none

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 418751910044649baa2b424ea31cce3fc4dcc253, 448dfecc7ff807822ecd47a5c052acedca7d09e8, 46aa80ef49594ed7de685ecbc673b291e9a2c159 +5

Exploitation evidence

Disclosed: evidence found.
CVE published 12 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.

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.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), 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

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ 22ada802ede89829dd010a317d9b812b7df7111a, < 418751910044649baa2b424ea31cce3fc4dcc253	Fixed in 418751910044649baa2b424ea31cce3fc4dcc253
LinuxLinux	Affected ≥ 22ada802ede89829dd010a317d9b812b7df7111a, < 448dfecc7ff807822ecd47a5c052acedca7d09e8	Fixed in 448dfecc7ff807822ecd47a5c052acedca7d09e8
LinuxLinux	Affected ≥ 22ada802ede89829dd010a317d9b812b7df7111a, < 46aa80ef49594ed7de685ecbc673b291e9a2c159	Fixed in 46aa80ef49594ed7de685ecbc673b291e9a2c159
LinuxLinux	Affected ≥ 22ada802ede89829dd010a317d9b812b7df7111a, < 31f2f080898e50cbf2bae62d35f9f2a997547b38	Fixed in 31f2f080898e50cbf2bae62d35f9f2a997547b38
LinuxLinux	Affected ≥ 22ada802ede89829dd010a317d9b812b7df7111a, < 14beeef4aafecc8a41de534e31fb5be94739392f	Fixed in 14beeef4aafecc8a41de534e31fb5be94739392f
LinuxLinux	Affected ≥ 22ada802ede89829dd010a317d9b812b7df7111a, < 8b3ce085b52e674290cbfdd07034e7653ffbe4dc	Fixed in 8b3ce085b52e674290cbfdd07034e7653ffbe4dc

AI-suggested

A fix is available and has been applied in multiple Linux kernel commits as indicated by the fixedVersions hashes. Users should update their Linux kernel to a version that includes these fixes to mitigate the vulnerability.

Description

CVE-2025-39795 is a vulnerability in the Linux kernel's block subsystem where an overflow could occur during a check on chunk_sectors in the blk_stack_limits() function. The issue arises because chunk_sectors was calculated in bytes, potentially overflowing the unsigned int variable. The fix changes the check to be based on sectors instead of bytes to avoid this overflow.

Impact

An overflow in the chunk_sectors check could lead to incorrect validation of block device parameters, potentially causing unexpected behavior in the block layer. The exact impact is not detailed in the input data, and no known exploits in the wild have been reported.

Summary

The vulnerability in the Linux kernel affects the blk_stack_limits() function, which verifies that the chunk_sectors value is a multiple of the physical_block_size. Previously, chunk_sectors was calculated in bytes, which could overflow the unsigned int holding it. This overflow could cause incorrect validation. The patch modifies the check to use sectors rather than bytes, preventing the overflow condition.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Nov 2026, 21:35 UTC

Technical details

References

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