CVE-2026-64324udf: validate free block extents against the partition length
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.8 HIGH (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Analyzed
- Record last updated
- Oct 16, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | from 934f815345c09c290a9b9a9cfdddc203ec2117e8 before fdd6229d2ae9914c1f25d1041db0f4f312a4fa76; from 22cc7323f090646c8cfb5939e6f15bdc2ed3fd27 before b54aee5652fcd7c23a0904a4623ec462c3edc70c; from 7c4fa9ebfce69619d132fe703dc2e2cf62a13723 before 12af328d2ee8d68e81ba612246d0b54b22d23e1f; from 5cc9745e2ea11aef7d5c9a42bc36f6cd3e1b4cc3 before fb49099206c5c57af28a157249fa7bcb5518f99e; from 56e69e59751d20993f243fb7dd6991c4e522424c before 9442d75429b0c556292a7454fe888d54259f5240; from 56e69e59751d20993f243fb7dd6991c4e522424c before 335202ab25b01fdd45889ff25eab70864686dea3; from 56e69e59751d20993f243fb7dd6991c4e522424c before be87de7789a82a030a4896bc7683415ec9fa6f2b; 56e69e59751d20993f243fb7dd6991c4e522424c builds before 5f0419457f89dce1a3f1c8e62a3adf2f39ab8168; and 10 more ranges | CNA record |
linux linux_kernel linux:linux_kernel | from 4.19.320 before 4.20; from 5.4.282 before 5.5; from 5.10.224 before 5.10.261; from 5.15.165 before 5.15.212; from 6.1.105 before 6.1.178; from 6.6.46 before 6.6.145; from 6.10.5 before 6.12.96; from 6.13 before 6.18.39; and 1 more ranges | NVD |
References
- https://git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76patch
- https://git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70cpatch
- https://git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1fpatch
- https://git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99epatch
- https://git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240patch
- https://git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3patch
- https://git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2bpatch
- https://git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168patch
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.