CVE-2025-40044: Linux kernel · fs: udf: fix OOB read in lengthAllocDescs handling
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1100.107~20.04.2 : patch Linux kernel soon.
Data as of 28 Oct 2026, 11:19 UTC
- Patch
- Available – fixed in 5.15.0-1100.107~20.04.2, 5.15.0-1110.119~20.04.1, 5.15.0-1100.109~20.04.1 +71
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 2025
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.
Patches and advisories
- ubuntu.com/security/notices/USN-8029-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8030-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8034-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8034-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8048-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-6 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linuxpkg:deb/ubuntu/linux?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 25.10linux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Ubuntu 25.10linux-oraclepkg:deb/ubuntu/linux-oracle?arch=source&distro=questingOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available and has been released in multiple Linux kernel versions starting from 5.15.0-1094.97~20.04.1 and later. Users and administrators should update their Linux kernel to one of the fixed versions to remediate this vulnerability. No additional mitigation steps are indicated by the vendor advisory.
Description
CVE-2025-40044 is a high-severity vulnerability in the Linux kernel's UDF filesystem driver that causes an out-of-bounds read due to improper validation of lengthAllocDescs when parsing Allocation Extent Descriptors. This can lead to a use-after-free condition detected by KASAN, potentially allowing an attacker to cause memory corruption. The issue is fixed in multiple Linux kernel versions starting from 5.15.0-1094.97~20.04.1 and later. The vulnerability was discovered by the Linux Verification Center using Syzkaller. A patch is available and should be applied to affected systems.
References
- ubuntu.com/security/CVE-2025-40044 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-40044 (opens in a new tab)
- git.kernel.org/linus/3bd5e45c2ce30e239d596becd5db720f7eb83c99 (opens in a new tab)
- git.kernel.org/stable/c/1d1847812a1a5375c10a2a779338df643f79c047 (opens in a new tab)
- git.kernel.org/stable/c/3bd5e45c2ce30e239d596becd5db720f7eb83c99 (opens in a new tab)
- git.kernel.org/stable/c/459404f858213967ccfff336c41747d8dd186d38 (opens in a new tab)
- git.kernel.org/stable/c/918649364fbca7d5df72522ca795479edcd25f91 (opens in a new tab)
- git.kernel.org/stable/c/a70dcfa8d0a0cc530a6af59483dfca260b652c1b (opens in a new tab)
- git.kernel.org/stable/c/b57f2d7d3e6bb89ed82330c5fe106cdfa34d3e24 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8030-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-8034-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-8029-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8033-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-8034-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8048-1 (opens in a new tab)