CVE-2026-45991

High

In the Linux kernel, the following vulnerability has been resolved: udf: fix partition descriptor append bookkeeping Mounting a crafted UDF image with repeated partition descriptors can trigger a heap out-of-bounds write in part_descs_loc[]. handle_partition_descriptor() deduplicates entries by partition number, but appended slots never record partnum. As a result duplicate Partition Descriptors are appended repeatedly and num_part_descs keeps growing. Once the table is full, the growth path still sizes the allocation from partnum even though inserts are indexed by num_part_descs. If partnum is already aligned to PART_DESC_ALLOC_STEP, ALIGN(partnum, step) can keep the old capacity and the next append writes past the end of the table. Store partnum in the appended slot and size growth from the next append count so deduplication and capacity tracking follow the same model.

Package Linux Kernel
Published 2026-05-27
Last modified 2026-05-30
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 4.18.7, 4.19 and later are affected. Fixed in 6.6.140, 6.12.88, 7.0.4, 7.1-rc1 and their respective stable series.

Affected from
≥ 4.18.7 ≥ 4.19
Fixed in
✓ 6.6.140 6.6.x ✓ 6.12.88 6.12.x ✓ 7.0.4 7.0.x ✓ 7.1-rc1

References

The following references provide additional information about CVE-2026-45991 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

4 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2026-45991?

    CVE-2026-45991 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 4.18.7 onward and has been patched in 6.6.140, 6.12.88, 7.0.4 and others. CVE-2026-45991 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-45991?

    CVE-2026-45991 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-45991?

    Yes — CVE-2026-45991 has been patched. Fixed versions include 6.6.140, 6.12.88, 7.0.4 and others. If you are running Linux kernel 4.18.7 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-45991 actively exploited?

    No — CVE-2026-45991 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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