CVE-2026-53320

Local denial of service via zero block number

Published Jun 26, 2026 · Updated Jun 26, 2026

Denial of service in the Linux Kernel NILFS2 subsystem allows local users to trigger a kernel warning via a crafted garbage-collection ioctl. nilfs_ioctl_mark_blocks_dirty() treats a zero bd_oblocknr as live after an absent-block lookup also produces zero, then marks a nonexistent block. The path requires CAP_SYS_ADMIN and a writable NILFS2 mount; the warning can interrupt the system, including a crash when warnings panic.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux Kernel NILFS2 subsystem allows local users to trigger a kernel warning via a crafted garbage-collection ioctl. nilfs_ioctl_mark_blocks_dirty() treats a zero bd_oblocknr as live after an absent-block lookup also produces zero, then marks a nonexistent block. The path requires CAP_SYS_ADMIN and a writable NILFS2 mount; the warning can interrupt the system, including a crash when warnings panic.

The record

CVE
CVE-2026-53320
Published
Jun 26, 2026
Updated
Jun 26, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Jun 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 26, 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=2.6.30
  2. Affected versionversion=7942b919f7321f95a777d396ff7894a7a83dc9b0 <4525658002be3ad310b16bf8db48c8adb6a55d32
  3. Affected versionversion=7942b919f7321f95a777d396ff7894a7a83dc9b0 <65e07964b4b2daf9a54e686cf0fa72d74a9648a8
  4. Affected versionversion=7942b919f7321f95a777d396ff7894a7a83dc9b0 <94094e70fe292c9566502772d4d4d6d6a99204b1
  5. Affected versionversion=7942b919f7321f95a777d396ff7894a7a83dc9b0 <9472d37799a0b9ff9b99639f35961ac2f0b3c9be
  6. Affected versionversion=7942b919f7321f95a777d396ff7894a7a83dc9b0 <b88f905d4449b70da6bda547be546e365e44352e
  7. Affected versionversion=7942b919f7321f95a777d396ff7894a7a83dc9b0 <be3e5d10643d3be1cbac9d9939f220a99253f980
  8. Affected versionversion=7942b919f7321f95a777d396ff7894a7a83dc9b0 <e0a0c4903cbba351f0f5b5d104960d3a5b23202f
  9. Affected versionversion=7942b919f7321f95a777d396ff7894a7a83dc9b0 <e5ff0ba4b6983cdbcc826efc201e7179ece5d46f

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.30; version=7942b919f7321f95a777d396ff7894a7a83dc9b0 <4525658002be3ad310b16bf8db48c8adb6a55d32; version=7942b919f7321f95a777d396ff7894a7a83dc9b0 <65e07964b4b2daf9a54e686cf0fa72d74a9648a8; version=7942b919f7321f95a777d396ff7894a7a83dc9b0 <94094e70fe292c9566502772d4d4d6d6a99204b1; version=7942b919f7321f95a777d396ff7894a7a83dc9b0 <9472d37799a0b9ff9b99639f35961ac2f0b3c9be; version=7942b919f7321f95a777d396ff7894a7a83dc9b0 <b88f905d4449b70da6bda547be546e365e44352e; version=7942b919f7321f95a777d396ff7894a7a83dc9b0 <be3e5d10643d3be1cbac9d9939f220a99253f980; version=7942b919f7321f95a777d396ff7894a7a83dc9b0 <e0a0c4903cbba351f0f5b5d104960d3a5b23202f; version=7942b919f7321f95a777d396ff7894a7a83dc9b0 <e5ff0ba4b6983cdbcc826efc201e7179ece5d46f

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application 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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