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CVE-2026-98872

freevxfs: don't BUG() on unknown typed-extent type

CVSS score

—

EPSS probability

—

Risk score

—

Published

3 h ago

Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

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Vulnerability description

DayBreach AI Explanation

Verified against sources

Linux kernel freevxfs file system kernel panic vulnerability

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%53

Short explanation

The vxfs_bmap_typed function in the Linux kernel freevxfs component triggers a BUG() call upon encountering unknown on-disk typed-extent types, causing a kernel crash. This can be reached via ioctl(FIBMAP) on a regular file.

Why does it matter?

This vulnerability can directly lead to kernel-level crashes through malformed or unknown extent types on disk, threatening service continuity.

What should be done?

  • Follow vendor advisories and update notifications
  • Apply the fix replacing BUG with WARN_ON_ONCE in vxfs_bmap.c
  • Review patch references released for affected versions
Note on uncertainty

The sources give limited detail on some technical conditions. Review the chain of evidence below before deciding how to act.

Chain of evidence and sources2 verified claims

vxfs_bmap_typed fonksiyonu bilinmeyen kapsam türlerinde BUG() çağrısı yaparak çekirdeği çökertir.

Bu zafiyet normal bir dosya üzerinde çalışan ioctl(FIBMAP) üzerinden tetiklenebilir.

Show the technical text from the sources

In the Linux kernel, the following vulnerability has been resolved: freevxfs: don't BUG() on unknown typed-extent type vxfs_bmap_typed() handles four typed-extent types and calls BUG() in its default case, so an on-disk typed extent with any other type value crashes the kernel. It is reachable from ioctl(FIBMAP) on a regular file: kernel BUG at fs/freevxfs/vxfs_bmap.c:230! RIP: vxfs_bmap_typed fs/freevxfs/vxfs_bmap.c:230 [inline] vxfs_bmap1+0x128a/0x12d0 fs/freevxfs/vxfs_bmap.c:257 Replace the BUG() with WARN_ON_ONCE() and return 0 -- the value vxfs_bmap_typed() already returns on failure (and from the DEV4 case above); vxfs_getblk() maps 0 to -EIO, so the ioctl fails cleanly.

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-98872 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1linuxLinux View
2linuxLinux View
Total affected vendors: 1|Products: 2

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
The sources have not yet published a verified CVSS metric.

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-98872 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-98872 weaknesses.

Official Sources and Advisories

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CVE-2026-98872 · freevxfs: don't BUG() on unknown…