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NVD / CVE Program· CNA Linux

CVE-2026-45912: ext4: don't cache extent during splitting extent

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: 0.12% (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 4c2d9dac4d328244f9365b0a1fa27ec802821820, 5b1f4290453314e11cd8e15c7baa8a9b76c19b23, 692103feca376ae4298c92aa8828015d20f1d87b.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 4c2d9dac4d328244f9365b0a1fa27ec802821820, 5b1f4290453314e11cd8e15c7baa8a9b76c19b23, 692103feca376ae4298c92aa8828015d20f1d87b 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: don't cache extent during splitting extent Caching extents during the splitting process is risky, as it may result in stale extents remaining in the status tree. Moreover, in most cases, the corresponding extent block entries are likely already cached before the split happens, making caching here not particularly useful. Assume we have an unwritten extent, and then DIO writes the first half. [UUUUUUUUUUUUUUUU] on-disk extent U: unwritten extent [UUUUUUUUUUUUUUUU] extent status tree |<- ->| ----> dio write this range First, when ext4_split_extent_at() splits this extent, it truncates the existing extent and then inserts a new one. During this process, this extent status entry may be shrunk, and calls to ext4_find_extent() and ext4_cache_extents() may occur, which could potentially insert the truncated range as a hole into the extent status tree. After the split is completed, this hole is not replaced with the correct status. [UUUUUUU|UUUUUUUU] on-disk extent U: unwritten extent [UUUUUUU|HHHHHHHH] extent status tree H: hole Then, the outer calling functions will not correct this remaining hole extent either. Finally, if we perform a delayed buffer write on this latter part, it will re-insert the delayed extent and cause an error in space accounting. In adition, if the unwritten extent cache is not shrunk during the splitting, ext4_cache_extents() also conflicts with existing extents when caching extents. In the future, we will add checks when caching extents, which will trigger a warning. Therefore, Do not cache extents that are being split.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Jun 24, 2026
EPSS
0.1% · 2th percentile
CWE
—

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%

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  • 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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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 kernel3.12 and later · before 5.10.252
  • linux linux kernel5.11 and later · before 5.15.202
  • linux linux kernel5.16 and later · before 6.1.165
  • linux linux kernel6.2 and later · before 6.6.128
  • linux linux kernel6.7 and later · before 6.12.75
  • linux linux kernel6.13 and later · before 6.18.14
  • linux linux kernel6.19 and later · before 6.19.4

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

    • 3.12affected
    • 107a7bd31ac003e42c0f966aa8e5b26947de6024 and later · before 8302b5b4aacdbb378f7b1216bb2ee782b5142415affected · git
    • 107a7bd31ac003e42c0f966aa8e5b26947de6024 and later · before 692103feca376ae4298c92aa8828015d20f1d87baffected · git
    • 107a7bd31ac003e42c0f966aa8e5b26947de6024 and later · before 4c2d9dac4d328244f9365b0a1fa27ec802821820affected · git
    • 107a7bd31ac003e42c0f966aa8e5b26947de6024 and later · before 93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036affected · git
    • 107a7bd31ac003e42c0f966aa8e5b26947de6024 and later · before 96007fd3c106aea773c1afae2d6f64cceb6da208affected · git
    • 107a7bd31ac003e42c0f966aa8e5b26947de6024 and later · before 5b1f4290453314e11cd8e15c7baa8a9b76c19b23affected · git
    • 107a7bd31ac003e42c0f966aa8e5b26947de6024 and later · before 9a2b95cdaf07785e2739199037bd9c0863ccc1beaffected · git
    • 107a7bd31ac003e42c0f966aa8e5b26947de6024 and later · before 8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79affected · git
    • before 3.12not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.18.14-16.18.14-1

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-2026-45909May 27, 2026 · clk: mediatek: Drop __initconst from gates
    31Monitor
  • ← EarlierCVE-2026-45911May 27, 2026 · usb: cdns3: fix role switching during resume
    22Monitor
  • Later →CVE-2026-45913May 27, 2026 · net: bridge: mcast: always update mdb_n_entries for vlan contexts
    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 Linux4c2d9dac4d328244f9365b0a1fa27ec802821820Vendor (CNA)
Linux Linux5b1f4290453314e11cd8e15c7baa8a9b76c19b23Vendor (CNA)
Linux Linux692103feca376ae4298c92aa8828015d20f1d87bVendor (CNA)
Linux Linux8302b5b4aacdbb378f7b1216bb2ee782b5142415Vendor (CNA)
Linux Linux8b4b19a2f96348d70bfa306ef7d4a13b0bcbea79Vendor (CNA)
Linux Linux93b2ebbbcb2e63cfc21a1946dfe91d3aa7952036Vendor (CNA)
Linux Linux96007fd3c106aea773c1afae2d6f64cceb6da208Vendor (CNA)
Linux Linux9a2b95cdaf07785e2739199037bd9c0863ccc1beVendor (CNA)
debian:linux6.1.170-1 · 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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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)

—

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.

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

Change log

  1. Fix✗ → ✓

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

References

Show all references (7 more)

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

All records