CVE-2026-90042Network attack vector

Kernel crash via vmalloc-backed filename decryption

Published Sep 16, 2026 · Updated Sep 16, 2026

Improper buffer handling in Linux 6.6 CephFS allows context-dependent attackers to trigger a kernel oops during encrypted filename processing. ceph_fname_to_usr passes vmalloc-backed MDS message slices to fscrypt's scatterlist decryption path, which requires linear-mapped buffers. Reachability requires encrypted CephFS filename processing and a message allocation that spills into vmalloc, with service interruption bounded to the affected kernel host.

CVSS severityUnavailable
Unscored
EPSS probabilityUnavailable
No score available in this record
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

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Summary

What happened

Improper buffer handling in Linux 6.6 CephFS allows context-dependent attackers to trigger a kernel oops during encrypted filename processing. ceph_fname_to_usr passes vmalloc-backed MDS message slices to fscrypt's scatterlist decryption path, which requires linear-mapped buffers. Reachability requires encrypted CephFS filename processing and a message allocation that spills into vmalloc, with service interruption bounded to the affected kernel host.

The record

CVE
CVE-2026-90042
Published
Sep 16, 2026
Updated
Sep 16, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
network
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=457117f077c6749d1e28469eae91fb69c9806768 <110747ff535e3d98ac17d68dbd056bb6ef000e23
  2. Affected versionversion=457117f077c6749d1e28469eae91fb69c9806768 <3b467c68803d7c7e82678289e598afd44faa6101
  3. Affected versionversion=457117f077c6749d1e28469eae91fb69c9806768 <e939fc6a7bd969a58a150b7f188c1047138403e3
  4. Affected versionversion=6.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=457117f077c6749d1e28469eae91fb69c9806768 <110747ff535e3d98ac17d68dbd056bb6ef000e23; version=457117f077c6749d1e28469eae91fb69c9806768 <3b467c68803d7c7e82678289e598afd44faa6101; version=457117f077c6749d1e28469eae91fb69c9806768 <e939fc6a7bd969a58a150b7f188c1047138403e3; version=6.6

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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