CVE-2026-31577

Local system crash via uninitialized DAT cache

Published Apr 24, 2026 · Updated Apr 24, 2026

NULL pointer dereference in Linux Kernel NILFS2 allows local users to crash the system through a segment-cleaning ioctl. The nilfs_mdt_save_to_shadow_map() path copies dirty pages during garbage collection and dereferences the DAT inode's i_assoc_inode cache even when no earlier B-tree operation has initialized it. Triggering NILFS_IOCTL_CLEAN_SEGMENTS immediately after mounting a NILFS2 volume, before any DAT B-tree operation, causes a general protection fault and system crash.

CVSS severity5.5
Medium
EPSS probability0.13%
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 NILFS2 allows local users to crash the system through a segment-cleaning ioctl. The nilfs_mdt_save_to_shadow_map() path copies dirty pages during garbage collection and dereferences the DAT inode's i_assoc_inode cache even when no earlier B-tree operation has initialized it. Triggering NILFS_IOCTL_CLEAN_SEGMENTS immediately after mounting a NILFS2 volume, before any DAT B-tree operation, causes a general protection fault and system crash.

The record

CVE
CVE-2026-31577
Published
Apr 24, 2026
Updated
Apr 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 24, 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 <41de342278ae025c99cc8d33648773f05e306cf1
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <449ec5fc99f45974525ba9eea16b6670c45cd363
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <97fb7afec404912d967a7d4715f37742666b3084
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c36e206f302f1ddefed92d09ecbba070e1ae079e

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <41de342278ae025c99cc8d33648773f05e306cf1; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <449ec5fc99f45974525ba9eea16b6670c45cd363; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <97fb7afec404912d967a7d4715f37742666b3084; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <c36e206f302f1ddefed92d09ecbba070e1ae079e

Published CVSS scores

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application or System Exploitation

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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