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NVD / CVE Program· CNA Linux

CVE-2025-21736: nilfs2: fix possible int overflows in nilfs_fiemap()

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: 0.25% (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 250423300b4b0335918be187ef3cade248c06e6a, 58b1c6881081f5ddfb9a14dc241a74732c0f855c, 6438ef381c183444f7f9d1de18f22661cba1e946; azl3 kernel 6.6.64.2-9 on Azure Linux 3.0 6.6.78.1-3; azl3 kernel 6.6.78.1-3 on Azure Linux 3.0 6.6.78.1-3.

Low priority for now. Upgrade to Linux Linux 250423300b4b0335918be187ef3cade248c06e6a, 58b1c6881081f5ddfb9a14dc241a74732c0f855c, 6438ef381c183444f7f9d1de18f22661cba1e946; azl3 kernel 6.6.64.2-9 on Azure Linux 3.0 6.6.78.1-3; azl3 kernel 6.6.78.1-3 on Azure Linux 3.0 6.6.78.1-3 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: nilfs2: fix possible int overflows in nilfs_fiemap() Since nilfs_bmap_lookup_contig() in nilfs_fiemap() calculates its result by being prepared to go through potentially maxblocks == INT_MAX blocks, the value in n may experience an overflow caused by left shift of blkbits. While it is extremely unlikely to occur, play it safe and cast right hand expression to wider type to mitigate the issue. Found by Linux Verification Center (linuxtesting.org) with static analysis tool SVACE.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 26, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 17th 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 · 0.2%

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

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • 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

Affected versions

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

  • linux linux kernel2.6.38 and later · before 6.1.129
  • linux linux kernel6.2 and later · before 6.6.78
  • linux linux kernel6.7 and later · before 6.12.14
  • linux linux kernel6.13 and later · before 6.13.3

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

    • 2.6.38affected
    • 622daaff0a8975fb5c5b95f24f3234550ba32e92 and later · before 7649937987fed51ed09985da4019d50189fc534eaffected · git
    • 622daaff0a8975fb5c5b95f24f3234550ba32e92 and later · before 58b1c6881081f5ddfb9a14dc241a74732c0f855caffected · git
    • 622daaff0a8975fb5c5b95f24f3234550ba32e92 and later · before 8f41df5fd4c11d26e929a85f7239799641f92da7affected · git
    • 622daaff0a8975fb5c5b95f24f3234550ba32e92 and later · before f3d80f34f58445355fa27b9579a449fb186aa64eaffected · git
    • 622daaff0a8975fb5c5b95f24f3234550ba32e92 and later · before f2bd0f1ab47822fe5bd699c8458b896c4b2edea1affected · git
    • 622daaff0a8975fb5c5b95f24f3234550ba32e92 and later · before b9495a9109abc31d3170f7aad7d48aa64610a1a2affected · git
    • 622daaff0a8975fb5c5b95f24f3234550ba32e92 and later · before 250423300b4b0335918be187ef3cade248c06e6aaffected · git
    • 622daaff0a8975fb5c5b95f24f3234550ba32e92 and later · before 6438ef381c183444f7f9d1de18f22661cba1e946affected · git
    • before 2.6.38not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.129-16.1.129-1
Debian:13linuxbefore 6.12.15-16.12.15-1

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-2024-58021Feb 26, 2025 · HID: winwing: Add NULL check in winwing_init_led()
    22Monitor
  • ← EarlierCVE-2025-21734Feb 26, 2025 · misc: fastrpc: Fix copy buffer page size
    31Monitor
  • Later →CVE-2025-21737Feb 26, 2025 · ceph: fix memory leak in ceph_mds_auth_match()
    22Monitor

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 Linux250423300b4b0335918be187ef3cade248c06e6aVendor (CNA)
Linux Linux58b1c6881081f5ddfb9a14dc241a74732c0f855cVendor (CNA)
Linux Linux6438ef381c183444f7f9d1de18f22661cba1e946Vendor (CNA)
Linux Linux7649937987fed51ed09985da4019d50189fc534eVendor (CNA)
Linux Linux8f41df5fd4c11d26e929a85f7239799641f92da7Vendor (CNA)
Linux Linuxb9495a9109abc31d3170f7aad7d48aa64610a1a2Vendor (CNA)
Linux Linuxf2bd0f1ab47822fe5bd699c8458b896c4b2edea1Vendor (CNA)
Linux Linuxf3d80f34f58445355fa27b9579a449fb186aa64eVendor (CNA)
azl3 kernel 6.6.64.2-9 on Azure Linux 3.06.6.78.1-3 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.78.1-3 on Azure Linux 3.06.6.78.1-3 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.179.1-1 on CBL Mariner 2.05.15.179.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.182.1-1 on CBL Mariner 2.0CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 kernel 5.15.182.1-1 on CBL-Mariner 2.05.15.179.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.129-1 · 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-2026-31633422 days apartrxrpc: Fix integer overflow in rxgk_verify_response()
    39Monitor
  • CVE-2026-31649422 days apartnet: stmmac: fix integer underflow in chain mode
    39Monitor
  • CVE-2026-31659422 days apartbatman-adv: reject oversized global TT response buffers
    39Monitor
  • CVE-2026-43341436 days apartnet/ipv6: ioam6: prevent schema length wraparound in trace fill
    39Monitor
  • CVE-2026-46039455 days apartrxgk: Fix potential integer overflow in length check
    39Monitor
  • CVE-2026-46325468 days apartRDMA/rxe: Fix iova-to-va conversion for MR page sizes != PAGE_SIZE
    39Monitor

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-190 · Integer Overflow or Wraparound

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 (9 more)

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

All records