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NVD / CVE Program· CNA Linux

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

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 14beeef4aafecc8a41de534e31fb5be94739392f, 31f2f080898e50cbf2bae62d35f9f2a997547b38, 3b9d69f0e68aa6b0acd9791c45d445154a8c66e9; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1.

Low priority for now. Upgrade to Linux Linux 14beeef4aafecc8a41de534e31fb5be94739392f, 31f2f080898e50cbf2bae62d35f9f2a997547b38, 3b9d69f0e68aa6b0acd9791c45d445154a8c66e9; azl3 kernel 6.6.96.2-2 on Azure Linux 3.0 6.6.104.2-1; cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.0 5.15.200.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: block: avoid possible overflow for chunk_sectors check in blk_stack_limits() In blk_stack_limits(), we check that the t->chunk_sectors value is a multiple of the t->physical_block_size value. However, by finding the chunk_sectors value in bytes, we may overflow the unsigned int which holds chunk_sectors, so change the check to be based on sectors.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Sep 12, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 6th percentile

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel
debiandebian linux

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • debian debian linux11.0
  • linux linux kernel5.11 and later · before 5.15.190
  • linux linux kernel5.16 and later · before 6.1.149
  • linux linux kernel6.2 and later · before 6.6.103
  • linux linux kernel5.10 and later · before 5.10.241
  • linux linux kernel6.13 and later · before 6.15.11
  • linux linux kernel6.16 and later · before 6.16.2
  • linux linux kernel6.7 and later · before 6.12.43

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.10affected
    • 22ada802ede89829dd010a317d9b812b7df7111a and later · before 418751910044649baa2b424ea31cce3fc4dcc253affected · git
    • 22ada802ede89829dd010a317d9b812b7df7111a and later · before 8b3ce085b52e674290cbfdd07034e7653ffbe4dcaffected · git
    • 22ada802ede89829dd010a317d9b812b7df7111a and later · before 31f2f080898e50cbf2bae62d35f9f2a997547b38affected · git
    • 22ada802ede89829dd010a317d9b812b7df7111a and later · before 3b9d69f0e68aa6b0acd9791c45d445154a8c66e9affected · git
    • 22ada802ede89829dd010a317d9b812b7df7111a and later · before 46aa80ef49594ed7de685ecbc673b291e9a2c159affected · git
    • 22ada802ede89829dd010a317d9b812b7df7111a and later · before 5e276e6ff9aacf8901b9c3265c3cdd2568c9fff2affected · git
    • 22ada802ede89829dd010a317d9b812b7df7111a and later · before 14beeef4aafecc8a41de534e31fb5be94739392faffected · git
    • 22ada802ede89829dd010a317d9b812b7df7111a and later · before 448dfecc7ff807822ecd47a5c052acedca7d09e8affected · git
    • before 5.10not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.153-16.1.153-1
Debian:13linuxbefore 6.12.43-16.12.43-1
Debian:14linuxbefore 6.16.3-16.16.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2025-39793Sep 12, 2025 · io_uring/memmap: cast nr_pages to size_t before shifting
    31Monitor
  • ← EarlierCVE-2025-39794Sep 12, 2025 · ARM: tegra: Use I/O memcpy to write to IRAM
    22Monitor
  • Later →CVE-2025-39796Sep 12, 2025 · net: lapbether: ignore ops-locked netdevs
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux14beeef4aafecc8a41de534e31fb5be94739392fVendor (CNA)
Linux Linux31f2f080898e50cbf2bae62d35f9f2a997547b38Vendor (CNA)
Linux Linux3b9d69f0e68aa6b0acd9791c45d445154a8c66e9Vendor (CNA)
Linux Linux418751910044649baa2b424ea31cce3fc4dcc253Vendor (CNA)
Linux Linux448dfecc7ff807822ecd47a5c052acedca7d09e8Vendor (CNA)
Linux Linux46aa80ef49594ed7de685ecbc673b291e9a2c159Vendor (CNA)
Linux Linux5e276e6ff9aacf8901b9c3265c3cdd2568c9fff2Vendor (CNA)
Linux Linux8b3ce085b52e674290cbfdd07034e7653ffbe4dcVendor (CNA)
azl3 kernel 6.6.96.2-2 on Azure Linux 3.06.6.104.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.186.1-1 on CBL Mariner 2.05.15.200.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.153-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-43185236 days apartksmbd: fix signededness bug in smb_direct_prepare_negotiation()
    39Monitor
  • CVE-2025-3845949 days apartatm: clip: Fix infinite recursive call of clip_push().
    31Monitor
  • CVE-2026-53202286 days apartaccel/ivpu: Fix signed integer truncation in IPC receive
    31Monitor
  • CVE-2026-53267286 days apartnetfilter: nft_ct: bail out on template ct in get eval
    31Monitor
  • CVE-2024-35886481 days apartipv6: Fix infinite recursion in fib6_dump_done().
    31Monitor
  • CVE-2026-53395310 days apartnfsd: fix dead ACL conflict guard in nfsd4_create
    30Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-674 · Uncontrolled Recursion

CVSS vector

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

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (13 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records