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NVD / CVE Program· CNA Linux

CVE-2025-40198: ext4: avoid potential buffer over-read in parse_apply_sb_mount_options()

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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: 0.16% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 01829af7656b56d83682b3491265d583d502e502, 2a0cf438320cdb783e0378570744c0ef0d83e934, 7bf46ff83a0ef11836e38ebd72cdc5107209342d; azl3 kernel 6.6.112.1-2 on Azure Linux 3.0 6.6.117.1-1.

Low priority for now. Upgrade to Linux Linux 01829af7656b56d83682b3491265d583d502e502, 2a0cf438320cdb783e0378570744c0ef0d83e934, 7bf46ff83a0ef11836e38ebd72cdc5107209342d; azl3 kernel 6.6.112.1-2 on Azure Linux 3.0 6.6.117.1-1 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: ext4: avoid potential buffer over-read in parse_apply_sb_mount_options() Unlike other strings in the ext4 superblock, we rely on tune2fs to make sure s_mount_opts is NUL terminated. Harden parse_apply_sb_mount_options() by treating s_mount_opts as a potential __nonstring.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Nov 12, 2025
Updated
Oct 19, 2026
EPSS
0.1% · 5th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · Linux
7.8
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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.

Follow CVE-2025-40198

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.

—

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

    • 2.6.36affected
    • 8b67f04ab9de5d8f3a71aef72bf02c995a506db5 and later · before 7bf46ff83a0ef11836e38ebd72cdc5107209342daffected · git
    • 8b67f04ab9de5d8f3a71aef72bf02c995a506db5 and later · before b2bac84fde28fb6a88817b8b761abda17a1d300baffected · git
    • 8b67f04ab9de5d8f3a71aef72bf02c995a506db5 and later · before e651294218d2684302ee5ed95ccf381646f3e5b4affected · git
    • 8b67f04ab9de5d8f3a71aef72bf02c995a506db5 and later · before 01829af7656b56d83682b3491265d583d502e502affected · git
    • 8b67f04ab9de5d8f3a71aef72bf02c995a506db5 and later · before 2a0cf438320cdb783e0378570744c0ef0d83e934affected · git
    • 8b67f04ab9de5d8f3a71aef72bf02c995a506db5 and later · before a6e94557cd05adc82fae0400f6e17745563e5412affected · git
    • 8b67f04ab9de5d8f3a71aef72bf02c995a506db5 and later · before 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8affected · git
    • before 2.6.36not affected · semver
    • 5.4.301 and later · up to and including 5.4.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.158-16.1.158-1
Debian:13linuxbefore 6.12.57-16.12.57-1
Debian:14linuxbefore 6.17.6-16.17.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40196Nov 12, 2025 · fs: quota: create dedicated workqueue for quota_release_work
    0Monitor
  • ← EarlierCVE-2025-40197Nov 12, 2025 · media: mc: Clear minor number before put device
    0Monitor
  • Later →CVE-2025-40199Nov 12, 2025 · page_pool: Fix PP_MAGIC_MASK to avoid crashing on some 32-bit arches
    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 Linux01829af7656b56d83682b3491265d583d502e502Vendor (CNA)
Linux Linux2a0cf438320cdb783e0378570744c0ef0d83e934Vendor (CNA)
Linux Linux7bf46ff83a0ef11836e38ebd72cdc5107209342dVendor (CNA)
Linux Linux8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8Vendor (CNA)
Linux Linuxa6e94557cd05adc82fae0400f6e17745563e5412Vendor (CNA)
Linux Linuxb2bac84fde28fb6a88817b8b761abda17a1d300bVendor (CNA)
Linux Linuxe651294218d2684302ee5ed95ccf381646f3e5b4Vendor (CNA)
azl3 kernel 6.6.112.1-2 on Azure Linux 3.06.6.117.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.158-1 · 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.

No nightly-computed relations.

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.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. SSVC exploitation— → none
  2. Fix✗ → ✓

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

References

Show all references (6 more)

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

All records