CVE Intelligence
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CVE-2026-89567 — jbd2: bound shrinker scans by examined checkpoint buffers

In the Linux kernel, the following vulnerability has been resolved: jbd2: bound shrinker scans by examined checkpoint buffers The jbd2 shrinker currently accounts only checkpoint buffers that it successfully releases against nr_to_scan. Busy buffers therefore do not consume the scan budget. If a checkpoint transaction contains mostly busy buffers, the shrinker can scan its entire checkpoint list while holding journal->j_list_lock. Large checkpoint lists can result in excessive lock hold times and leave other CPUs spinning on j_list_lock, causing soft lockups or RCU stalls. Pass nr_to_scan into journal_shrink_one_cp_list() and decrement it for every buffer examined, including busy buffers. Pass NULL from checkpoint cleanup paths so their existing full-list behavior is preserved. This restores the scan-budget semantics that existed before journal_shrink_one_cp_list() was changed to always scan a complete checkpoint list.

Published Sep 11, 2026 · Updated Oct 21, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+2

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.21%
ahead of 10% of scored CVEs · Oct 22, 2026
Affects
Linux
Linux
CVSS base
—
Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ b98dba273a0e47dbfade89c9af73c5b012a4eabb and < edf5fcd0469b7467bd5b37a79502c8d9c3257dbb≥ b98dba273a0e47dbfade89c9af73c5b012a4eabb and < 71c6b872c746465fa4b5def239cb296173ca8216≥ b98dba273a0e47dbfade89c9af73c5b012a4eabb and < c2c0fb364685b8996c357d3b050394959b29d6e0≥ b98dba273a0e47dbfade89c9af73c5b012a4eabb and < 15cb16496446b94e67f7abcb049b8e2c75cd3d02version 9c31bb2684f8035beca0275349d19d679b679ffbversion 5fda50e262e65bd553ff777c4b280afd1495a18bversion 557fda9ed70ebf8eda2620ba3d746215285a1303≥ 5.15.129 and < 5.16
and 4 more ≥ 6.1.50 and < 6.2≥ 6.4.13 and < 6.5version 6.5≥ b98dba273a0e47dbfade89c9af73c5b012a4eabb and < 6b5366ba63a58819396045ab146bd37ff9e503c6
Vulnerable CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 22, 2026 · 7 reading(s) · max 0.21%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · linux/linux
    Oct 21, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 15, 2026
  • Affected products added · linux/linux
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Sep 11, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 19, 2026 – Oct 21, 2026
  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

7 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-98869 bpf: Infer zext_dst based on static register liveness analysis 1d
  • CVE-2023-7356 Bluetooth: ISO: Copy BASE if service data matches EIR_BAA_SERVICE_UUID 1d
  • CVE-2026-98866 sched/cache: Introduce task_struct->sched_cache_grp to fix UAF 4d
  • CVE-2026-98867 dm-pcache: bound the logical key offset from persistent memory 4d
  • CVE-2026-98868 dm-pcache: reject a kset that overruns its segment 4d
  • CVE-2026-98856 kprobes: Skip disarmed probes when checking optkprobe overlap 4d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CVSS score published by NVD, the CNA, CISA or GitHub so far.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-89567 is "jbd2: bound shrinker scans by examined checkpoint buffers", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.21% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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