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VulnerabilityPublished

CVE-2026-99274: Linux kernel · smb: client: fix fiemap wild read on empty truncated response

Affects Linux kernelSource GCVE Database

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Authoritative record:CVE-2026-99274· High

Not known to be exploited.

Data as of 10 Nov 2026, 07:11 UTC

Severity
High

Rated by Threat Radar · CVSS not yet scored by NVD

Thin evidence

One scorer or none

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 9 Nov 2026.

What to do

Affected software

ProductAffectedFixed in
Ubuntu 26.10linuxpkg:deb/ubuntu/linux?arch=source&distro=stonkingOther threatsAffected
  • 7.0.0-14.14 – 7.3.0-10.10
7 affected builds
Fixed in–
Ubuntu 26.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=stonkingOther threatsAffected
  • 7.0.0-1004.4 – 7.3.0-1004.4
6 affected builds
Fixed in–
Ubuntu 26.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=stonkingOther threatsAffected
  • 7.0.0-1004.4 – 7.3.0-1004.4
6 affected builds
Fixed in–
Ubuntu 26.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=stonkingOther threatsAffected
  • 7.0.0-1004.4 – 7.3.0-1004.5
4 affected builds
Fixed in–
Ubuntu 26.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=stonkingOther threatsAffected
  • 7.0.0-1003.3 – 7.3.0-1004.4
6 affected builds
Fixed in–
Ubuntu 26.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=stonkingOther threatsAffected
  • 7.0.0-1003.3 – 7.3.0-1004.4
6 affected builds
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix for this vulnerability is available and should be applied. The patch rejects empty truncated range blobs and adds necessary checks to prevent wild reads and infinite loops. Users should update to fixed kernel versions or apply the vendor's official patches. No additional mitigation is required beyond applying the fix.

Description

A vulnerability in the Linux kernel SMB client (smb3_fiemap) allows a wild read from an empty truncated response when handling FSCTL_QUERY_ALLOCATED_RANGES requests. This occurs because the client incorrectly processes a STATUS_BUFFER_OVERFLOW response with zero output count, leading to an out-of-bounds memory read and potential kernel crash (oops). The issue has been reproduced on version 6.6.87.2 with a malicious SMB2 server. The vulnerability is fixed by rejecting empty truncated range blobs and adding additional checks to prevent infinite loops and memory underflows.

References

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