CVE-2026-22991Network attack vector

Remote crash via partial allocation cleanup

Published Jan 23, 2026 · Updated Jan 23, 2026

NULL pointer dereference in Linux kernel libceph allows remote attackers to crash systems while processing a Ceph OSD map. In decode_choose_args(), arg_map->size becomes nonzero before arg_map->args allocation, so failure cleanup calls free_choose_arg_map() and iterates through a NULL array. Reachability requires allocation failure during OSD map decoding, and the reported consequence is loss of system availability.

CVSS severity7.5
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in Linux kernel libceph allows remote attackers to crash systems while processing a Ceph OSD map. In decode_choose_args(), arg_map->size becomes nonzero before arg_map->args allocation, so failure cleanup calls free_choose_arg_map() and iterates through a NULL array. Reachability requires allocation failure during OSD map decoding, and the reported consequence is loss of system availability.

The record

CVE
CVE-2026-22991
Published
Jan 23, 2026
Updated
Jan 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 23, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8081faaf089db5280c3be820948469f7c58ef8dd
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <851241d3f78a5505224dc21c03d8692f530256b4
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9b3730dabcf3764bfe3ff07caf55e641a0b45234
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c4c2152a858c0ce4d2bff6ca8c1d5b0ef9f2cbdf
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e3fe30e57649c551757a02e1cad073c47e1e075e
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ec1850f663da64842614c86b20fe734be070c2ba
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f21c3fdb96833aac2f533506899fe38c19cf49d5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <8081faaf089db5280c3be820948469f7c58ef8dd; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <851241d3f78a5505224dc21c03d8692f530256b4; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <9b3730dabcf3764bfe3ff07caf55e641a0b45234; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c4c2152a858c0ce4d2bff6ca8c1d5b0ef9f2cbdf; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e3fe30e57649c551757a02e1cad073c47e1e075e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ec1850f663da64842614c86b20fe734be070c2ba; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f21c3fdb96833aac2f533506899fe38c19cf49d5

Published CVSS scores

7.5kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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