CVE-2026-64324: Linux kernel · Out-of-bounds Read
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in fdd6229d2ae9914c1f25d1041db0f4f312a4fa76 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:30 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- CISA SSVC
- Exploitation
- No evidence of active exploitation and no public proof of concept
- Automatable
- Attackers cannot reliably automate steps 1–4 of the kill chain
- Technical impact
- Total control over the software or total information disclosure
CISA SSVC assessment, 2026-10-16.
- Patch
- Available – fixed in fdd6229d2ae9914c1f25d1041db0f4f312a4fa76, fb49099206c5c57af28a157249fa7bcb5518f99e, be87de7789a82a030a4896bc7683415ec9fa6f2b +12
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 25 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
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.
References
- git.kernel.org/stable/c/fdd6229d2ae9914c1f25d1041db0f4f312a4fa76 (opens in a new tab)
- git.kernel.org/stable/c/b54aee5652fcd7c23a0904a4623ec462c3edc70c (opens in a new tab)
- git.kernel.org/stable/c/12af328d2ee8d68e81ba612246d0b54b22d23e1f (opens in a new tab)
- git.kernel.org/stable/c/fb49099206c5c57af28a157249fa7bcb5518f99e (opens in a new tab)
- git.kernel.org/stable/c/9442d75429b0c556292a7454fe888d54259f5240 (opens in a new tab)
- git.kernel.org/stable/c/335202ab25b01fdd45889ff25eab70864686dea3 (opens in a new tab)
- git.kernel.org/stable/c/be87de7789a82a030a4896bc7683415ec9fa6f2b (opens in a new tab)
- git.kernel.org/stable/c/5f0419457f89dce1a3f1c8e62a3adf2f39ab8168 (opens in a new tab)