CVE-2026-64324udf: validate free block extents against the partition length

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.

Timeline

Scores

EPSS (exploitation in 30 days)

0.16% · top 95% of all CVEs (15 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.

Affected products

• Linux · Linux

  • affected 934f815345c09c290a9b9a9cfdddc203ec2117e8 – < fdd6229d2ae9914c1f25d1041db0f4f312a4fa76
  • affected 22cc7323f090646c8cfb5939e6f15bdc2ed3fd27 – < b54aee5652fcd7c23a0904a4623ec462c3edc70c
  • affected 7c4fa9ebfce69619d132fe703dc2e2cf62a13723 – < 12af328d2ee8d68e81ba612246d0b54b22d23e1f
  • affected 5cc9745e2ea11aef7d5c9a42bc36f6cd3e1b4cc3 – < fb49099206c5c57af28a157249fa7bcb5518f99e
  • affected 56e69e59751d20993f243fb7dd6991c4e522424c – < 9442d75429b0c556292a7454fe888d54259f5240
  • affected 56e69e59751d20993f243fb7dd6991c4e522424c – < 335202ab25b01fdd45889ff25eab70864686dea3
  • affected 56e69e59751d20993f243fb7dd6991c4e522424c – < be87de7789a82a030a4896bc7683415ec9fa6f2b
  • affected 56e69e59751d20993f243fb7dd6991c4e522424c – < 5f0419457f89dce1a3f1c8e62a3adf2f39ab8168
  • affected 097420e48e30f51e8f4f650b5c946f5af63ec1a3
  • affected 5def895b42ef16a2da6402818cba8d7ec8ede1ef
  • affected 05fb2bf477d3fe5421bd4cb699574737f52bd88b
  • affected 5.10.224 – < 5.10.261
  • affected 5.15.165 – < 5.15.212
  • affected 6.1.105 – < 6.1.178
  • affected 6.6.46 – < 6.6.145
  • affected 4.19.320 – < 4.20
  • affected 5.4.282 – < 5.5
  • affected 6.10.5 – < 6.11

• Linux · Linux

  • affected 6.11
  • unaffected < 6.11
  • unaffected 5.10.261 – ≤ 5.10.*
  • unaffected 5.15.212 – ≤ 5.15.*
  • unaffected 6.1.178 – ≤ 6.1.*
  • unaffected 6.6.145 – ≤ 6.6.*
  • unaffected 6.12.96 – ≤ 6.12.*
  • unaffected 6.18.39 – ≤ 6.18.*
  • unaffected 7.1.4 – ≤ 7.1.*
  • unaffected 7.2 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-48868 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-64324](https://cveledger.app/badge/CVE-2026-64324.svg)](https://cveledger.app/cve/CVE-2026-64324)

Record last updated 19 Oct 2026, 20:38 UTC.