CVE-2025-39730: Linux kernel · NFS: Fix filehandle bounds checking in nfs_fh_to_dentry()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1097.104~20.04.1 : patch Linux kernel soon.
Data as of 28 Oct 2026, 11:27 UTC
- Patch
- Available – fixed in 5.15.0-1097.104~20.04.1, 5.15.0-1102.111~20.04.1, 5.15.0-1097.106~20.04.1 +63
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 7 Sep 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-7879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7880-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7909-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7909-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7909-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7910-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7909-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7910-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7933-1 (opens in a new tab)
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 25.10linux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-aws-6.14pkg:deb/ubuntu/linux-aws-6.14?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther 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, including 5.15.0-1097.104~20.04.1 and later. Users should update their Linux kernel packages to these fixed versions as provided by their distribution vendor, such as through the Ubuntu security advisory USN-7879-1. No additional mitigation steps are required beyond applying the official kernel updates.
Description
A vulnerability in the Linux kernel's NFS client code was fixed by improving filehandle bounds checking in the nfs_fh_to_dentry() function. The flaw involved insufficient verification of the minimal filehandle length before accessing embedded filehandles, potentially leading to memory safety issues. This vulnerability affects multiple specific Linux kernel versions, primarily in the linux-azure product line. The issue has been addressed in several patched kernel releases. The CVSS score is 7.8, indicating a high severity level with impacts on confidentiality, integrity, and availability.
References
- ubuntu.com/security/CVE-2025-39730 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-39730 (opens in a new tab)
- git.kernel.org/linus/ef93a685e01a281b5e2a25ce4e3428cf9371a205 (opens in a new tab)
- git.kernel.org/stable/c/12ad3def2e5e0b120e3d0cb6ce8b7b796819ad40 (opens in a new tab)
- git.kernel.org/stable/c/2ad40b7992aa26bc631afc1a995b0e3ddc30de3f (opens in a new tab)
- git.kernel.org/stable/c/3570ef5c31314c13274c935a20b91768ab5bf412 (opens in a new tab)
- git.kernel.org/stable/c/763810bb883cb4de412a72f338d80947d97df67b (opens in a new tab)
- git.kernel.org/stable/c/7dd36f7477d1e03a1fcf8d13531ca326c4fb599f (opens in a new tab)
- git.kernel.org/stable/c/7f8eca87fef7519e9c41f3258f25ebc2752247ee (opens in a new tab)
- git.kernel.org/stable/c/b7f7866932466332a2528fda099000b035303485 (opens in a new tab)
- git.kernel.org/stable/c/cb09afa0948d96b1e385d609ed044bb1aa043536 (opens in a new tab)
- git.kernel.org/stable/c/ef93a685e01a281b5e2a25ce4e3428cf9371a205 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7880-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7909-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7879-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7909-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7909-3 (opens in a new tab)