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Response snapshot Oct 26, 2026, 23:46 UTC

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VulnerabilityCVE-2026-98443

Linux kernel: xfs: fix cursor and pointer handling when recovering iunlink buckets

In the Linux kernel, the following vulnerability has been resolved: xfs: fix cursor and pointer handling when recovering iunlink buckets LOLLM pointed out a bug in xlog_recover_iunlink_bucket: 1.

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
0.1% in the next 30 days
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-98443 (opens a new tab)

What happened

In the Linux kernel, the following vulnerability has been resolved:

xfs: fix cursor and pointer handling when recovering iunlink buckets

LOLLM pointed out a bug in xlog_recover_iunlink_bucket:

1. We don't null out prev_ip after releasing it, which can lead to UAF problems if the inodegc flush call in the loop fails.

Continue reading

at which point I noticed even more bugs:

2. If the inodegc flush inside the loop fails, we also leak @ip.

3. We set prev_agino to agino having already advanced agino, which results in inodes with i_prev_unlinked set to itself.

4. If we exit the bottom of the loop with prev_ip set, then prev_ip aliases ip and we also set its i_prev_unlinked to itself.

Bugs 3 and 4 introduce loops into the unlinked list, though these loops don't surface because we immediately flush each unlinked inode after loading it.

Fix all of these issues.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

0.1%

Scored Percentile 3.0%

Model and measurement source (opens a new tab)

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-98443 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    FIRST measured EPSS score (opens a new tab)

    Measured EPSS probability and percentile for CVE-2026-98443, scored 2026-10-26. This is a model estimate, not proof of exposure.

    Published Checked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, October 24). Linux kernel: xfs: fix cursor and pointer handling when recovering iunlink buckets (CVE-2026-98443). https://kevwire.com/record/CVE-2026-98443

MLA

"Linux kernel: xfs: fix cursor and pointer handling when recovering iunlink buckets (CVE-2026-98443)." KEVWire, 24 Oct. 2026, kevwire.com/record/CVE-2026-98443.

Chicago

KEVWire. "Linux kernel: xfs: fix cursor and pointer handling when recovering iunlink buckets (CVE-2026-98443)." Last modified October 24, 2026. https://kevwire.com/record/CVE-2026-98443.

Evidence summary (plain text)

Linux kernel: xfs: fix cursor and pointer handling when recovering iunlink buckets (Oct 18, 2026).
In the Linux kernel, the following vulnerability has been resolved:

xfs: fix cursor and pointer handling when recovering iunlink buckets

LOLLM pointed out a bug in xlog_recover_iunlink_bucket:

1. We don't null out prev_ip after releasing it, which can lead to UAF
   problems if the inodegc flush call in the loop fails.

at which point I noticed even more bugs:

2. If the inodegc flush inside the loop fails, we also leak @ip.

3. We set prev_agino to agino having already advanced agino, which
   results in inodes with i_prev_unlinked set to itself.

4. If we exit the bottom of the loop with prev_ip set, then prev_ip
   aliases ip and we also set its i_prev_unlinked to itself.

Bugs 3 and 4 introduce loops into the unlinked list, though these loops
don't surface because we immediately flush each unlinked inode after
loading it.

Fix all of these issues.
CVSS 7.8 (version 3.1; evidence as of Oct 24, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-98443).
EPSS 0.1% for the following 30 days, scored Oct 26, 2026 (https://api.first.org/data/v1/epss?cve=CVE-2026-98443&date=2026-10-26).
Sources:
NVD CVE-2026-98443: https://nvd.nist.gov/vuln/detail/CVE-2026-98443
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?pubStartDate=2026-10-12T13:35:55.142Z&pubEndDate=2026-10-26T13:35:55.142Z&resultsPerPage=500&startIndex=4500
FIRST measured EPSS score: https://api.first.org/data/v1/epss?cve=CVE-2026-98443&date=2026-10-26
Record ID: CVE-2026-98443.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Oct 26, 2026, 19:40 UTC. Ingestion is not an independent editorial investigation.

NVD status: Received. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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Record details

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