CVE-2026-89566

Soft lockups via skipped reschedule check

Published Sep 11, 2026 · Updated Sep 11, 2026

Denial of service in Linux kernel jbd2 checkpoint shrinking allows attackers to cause soft lockups or RCU stalls under memory pressure. journal_shrink_one_cp_list() continues past busy buffers before evaluating need_resched(), permitting a full checkpoint-list walk while j_list_lock remains held. Reachability requires a large checkpoint list dominated by busy buffers during memory pressure; contending CPUs can then spin on the lock.

CVSS severityUnavailable
Unscored
EPSS probability0.20%
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 Linux kernel jbd2 checkpoint shrinking allows attackers to cause soft lockups or RCU stalls under memory pressure. journal_shrink_one_cp_list() continues past busy buffers before evaluating need_resched(), permitting a full checkpoint-list walk while j_list_lock remains held. Reachability requires a large checkpoint list dominated by busy buffers during memory pressure; contending CPUs can then spin on the lock.

The record

CVE
CVE-2026-89566
Published
Sep 11, 2026
Updated
Sep 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 11, 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=5.15.129 <5.16
  2. Affected versionversion=557fda9ed70ebf8eda2620ba3d746215285a1303
  3. Affected versionversion=5fda50e262e65bd553ff777c4b280afd1495a18b
  4. Affected versionversion=6.1.50 <6.2
  5. Affected versionversion=6.4.13 <6.5
  6. Affected versionversion=6.5
  7. Affected versionversion=9c31bb2684f8035beca0275349d19d679b679ffb
  8. Affected versionversion=b98dba273a0e47dbfade89c9af73c5b012a4eabb <595cac7f1b32d009b97f83dd2b2d6a1a445e9bb4
  9. Affected versionversion=b98dba273a0e47dbfade89c9af73c5b012a4eabb <f213e12ff5c9590b1034ae8da0e6d09665c772d0
  10. Affected versionversion=b98dba273a0e47dbfade89c9af73c5b012a4eabb <f83c23286e54180cdc83a36463a60003534cc290
  11. Affected versionversion=b98dba273a0e47dbfade89c9af73c5b012a4eabb <f9182a85991a0ad5cd2940df6db75f40ad90028c

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.15.129 <5.16; version=557fda9ed70ebf8eda2620ba3d746215285a1303; version=5fda50e262e65bd553ff777c4b280afd1495a18b; version=6.1.50 <6.2; version=6.4.13 <6.5; version=6.5; version=9c31bb2684f8035beca0275349d19d679b679ffb; version=b98dba273a0e47dbfade89c9af73c5b012a4eabb <595cac7f1b32d009b97f83dd2b2d6a1a445e9bb4; version=b98dba273a0e47dbfade89c9af73c5b012a4eabb <f213e12ff5c9590b1034ae8da0e6d09665c772d0; version=b98dba273a0e47dbfade89c9af73c5b012a4eabb <f83c23286e54180cdc83a36463a60003534cc290; version=b98dba273a0e47dbfade89c9af73c5b012a4eabb <f9182a85991a0ad5cd2940df6db75f40ad90028c

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

Weakness, pattern, technique

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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