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CVE Record

CVE-2026-45899: ext4: drop extent cache when splitting extent fails

In the Linux kernel, the following vulnerability has been resolved: ext4: drop extent cache when splitting extent fails When the split extent fails, we might leave some extents still being processed and return an error directly, which will result in stale extent entries remaining in the extent status tree. So drop all of the remaining potentially stale extents if the splitting fails.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

CVE-2026-45899 is a Linux kernel ext4 filesystem flaw. If an extent split fails, stale extent-status entries may remain cached. The public record confirms a kernel fix, but does not state business impact, attack requirements, or severity. Treat this as a kernel maintenance item until vendor advisories clarify risk.

Executive priority

Set priority as conditional: track and patch through the normal kernel update process, but escalate if your vendor assigns high impact or if critical ext4-backed systems cannot be updated promptly. Current public evidence is insufficient for emergency treatment.

Technical view

The ext4 fix drops potentially stale extent cache entries when extent splitting fails. Without the fix, the extent status tree may retain stale entries after an error path. The CVE record lists Linux kernel versions as affected and references stable kernel commits, but provides no CVSS, CWE, or impact classification.

Likely exposure

Exposure is likely limited to Linux systems using affected kernels with ext4 filesystems. The source bundle does not identify distributions, package versions, enabled configurations, or whether non-ext4 filesystems are exposed. Validate through kernel version, filesystem usage, and distro backport status.

Exploitation context

The source bundle does not report active exploitation, and KEV is false. It also does not describe a proof of concept, remote attack path, local privilege requirement, denial-of-service condition, or data-impact scenario. Do not assume exploitability beyond the stated kernel bug.

Researcher notes

Focus analysis on the ext4 error path where extent splitting fails and stale entries can remain in the extent status tree. The record names the fix behavior but omits exploitability, impact, and affected distribution mapping, so validation should avoid assumptions beyond kernel source and vendor backports.

Mitigation direction

  • Review Linux distribution advisories for CVE-2026-45899 backported kernel fixes.
  • Plan kernel updates to versions containing the referenced stable commits.
  • Prioritize systems using ext4 for critical workloads or shared infrastructure.
  • Use normal reboot or live-patching processes required by your kernel vendor.
  • Monitor CVE and vendor records for CVSS, impact, or exploit updates.

Validation and detection

  • Inventory Linux hosts and record running kernel versions.
  • Identify hosts with ext4 mounted filesystems.
  • Compare installed kernels against vendor advisories for this CVE.
  • Confirm patched kernel packages include the referenced upstream stable fixes.
  • Check vulnerability scanner findings against distribution backport notes.
Prepared
Confidence
medium
Sources
9

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2026-45899 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
0ADP providers
8Source links

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux107a7bd31ac003e42c0f966aa8e5b26947de6024, 107a7bd31ac003e42c0f966aa8e5b26947de6024, 107a7bd31ac003e42c0f966aa8e5b26947de6024, 107a7bd31ac003e42c0f966aa8e5b26947de6024, 107a7bd31ac003e42c0f966aa8e5b26947de6024, 107a7bd31ac003e42c0f966aa8e5b26947de6024, 107a7bd31ac003e42c0f966aa8e5b26947de6024unaffected
LinuxLinux3.12, 0, 5.10.253, 5.15.203, 6.6.130, 6.12.75, 6.18.14, 6.19.4, 7.0affected
Weakness

CWE details

No CWE listed

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