CVE-2026-64324: In the Linux kernel, the following vulnerability has been resolved: udf: validate free block extents against the partition length udf_free_blocks() ...

Description

In the Linux kernel, the following vulnerability has been resolved: udf: validate free block extents against the partition length udf_free_blocks() checks the logical block number and count against the partition length, but drops the extent offset from that final bound. A crafted extent can pass the guard while logicalBlockNum + offset + count points past the partition, which later indexes past the space bitmap array. A single ftruncate(2) on a file backed by such an extent reliably panics the kernel. This is a local availability issue. On desktop systems where UDisks/polkit allows the active user to mount removable UDF media without CAP_SYS_ADMIN, an unprivileged local user can supply the crafted filesystem and trigger the panic by truncating a writable file on it. Systems that require root or CAP_SYS_ADMIN to mount the image have a higher prerequisite. No confidentiality or integrity impact is claimed: the reproduced primitive is an out-of-bounds read of a bitmap pointer slot followed by a kernel panic. Use the already computed logicalBlockNum + offset + count value for the partition length check. Also make load_block_bitmap() reject an out-of-range block group before indexing s_block_bitmap[], so corrupted callers cannot walk past the flexible array.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

0.16%

5.2th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

Vendor	Product	Versions
Linux	Linux	>= 934f815345c09c290a9b9a9cfdddc203ec2117e8, < fdd6229d2ae9914c1f25d1041db0f4f312a4fa76; >= 22cc7323f090646c8cfb5939e6f15bdc2ed3fd27, < b54aee5652fcd7c23a0904a4623ec462c3edc70c; >= 7c4fa9ebfce69619d132fe703dc2e2cf62a13723, < 12af328d2ee8d68e81ba612246d0b54b22d23e1f; >= 5cc9745e2ea11aef7d5c9a42bc36f6cd3e1b4cc3, < fb49099206c5c57af28a157249fa7bcb5518f99e; >= 56e69e59751d20993f243fb7dd6991c4e522424c, < 9442d75429b0c556292a7454fe888d54259f5240; >= 56e69e59751d20993f243fb7dd6991c4e522424c, < 335202ab25b01fdd45889ff25eab70864686dea3; >= 56e69e59751d20993f243fb7dd6991c4e522424c, < be87de7789a82a030a4896bc7683415ec9fa6f2b; >= 56e69e59751d20993f243fb7dd6991c4e522424c, < 5f0419457f89dce1a3f1c8e62a3adf2f39ab8168; 097420e48e30f51e8f4f650b5c946f5af63ec1a3; 5def895b42ef16a2da6402818cba8d7ec8ede1ef; 05fb2bf477d3fe5421bd4cb699574737f52bd88b; >= 5.10.224, < 5.10.261; >= 5.15.165, < 5.15.212; >= 6.1.105, < 6.1.178; >= 6.6.46, < 6.6.145; >= 4.19.320, < 4.20; >= 5.4.282, < 5.5; >= 6.10.5, < 6.11
Linux	Linux	6.11

References

Timeline

Published: Jul 25, 2026
Last Modified: Aug 11, 2026
Status: Awaiting Analysis

Frequently Asked Questions

What is CVE-2026-64324?

In the Linux kernel, the following vulnerability has been resolved: udf: validate free block extents against the partition length udf_free_blocks() checks the logical block number and count against the partition length, but drops the extent offset from that final bound. A crafted extent can pass the guard while logicalBlockNum + offset + count points past the partition, which later indexes past the space bitmap array. A single ftruncate(2) on a file backed by such an extent reliably panics the kernel. This is a local availability issue. On desktop systems where UDisks/polkit allows the active user to mount removable UDF media without CAP_SYS_ADMIN, an unprivileged local user can supply the crafted filesystem and trigger the panic by truncating a writable file on it. Systems that require root or CAP_SYS_ADMIN to mount the image have a higher prerequisite. No confidentiality or integrity impact is claimed: the reproduced primitive is an out-of-bounds read of a bitmap pointer slot followed by a kernel panic. Use the already computed logicalBlockNum + offset + count value for the partition length check. Also make load_block_bitmap() reject an out-of-range block group before indexing s_block_bitmap[], so corrupted callers cannot walk past the flexible array.

How severe is CVE-2026-64324?

CVE-2026-64324 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 0.16% probability of exploitation in the next 30 days.

How do I fix CVE-2026-64324?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →