CVE-2025-38058: Linux kernel · __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High · fixed in 5.15.0-1090.97~20.04.1 : patch Linux kernel soon.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.15.0-1090.97~20.04.1, 5.15.0-1094.103~20.04.1, 5.15.0-1114.123~20.04.1 +64
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 18 Jun 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-7704-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7711-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7770-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7771-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-2 (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.
Description
In the Linux kernel, the following vulnerability has been resolved: __legitimize_mnt(): check for MNT_SYNC_UMOUNT should be under mount_lock ... or we risk stealing final mntput from sync umount - raising mnt_count after umount(2) has verified that victim is not busy, but before it has set MNT_SYNC_UMOUNT; in that case __legitimize_mnt() doesn't see that it's safe to quietly undo mnt_count increment and leaves dropping the reference to caller, where it'll be a full-blown mntput(). Check under mount_lock is needed; leaving the current one done before taking that makes no sense - it's nowhere near common enough to bother with.
References
- ubuntu.com/security/CVE-2025-38058 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-38058 (opens in a new tab)
- git.kernel.org/linus/250cf3693060a5f803c5f1ddc082bb06b16112a9 (opens in a new tab)
- git.kernel.org/stable/c/250cf3693060a5f803c5f1ddc082bb06b16112a9 (opens in a new tab)
- git.kernel.org/stable/c/628fb00195ce21a90cf9e4e3d105cd9e58f77b40 (opens in a new tab)
- git.kernel.org/stable/c/8cafd7266fa02e0863bacbf872fe635c0b9725eb (opens in a new tab)
- git.kernel.org/stable/c/9b0915e72b3cf52474dcee0b24a2f99d93e604a3 (opens in a new tab)
- git.kernel.org/stable/c/b55996939c71a3e1a38f3cdc6a8859797efc9083 (opens in a new tab)
- git.kernel.org/stable/c/b89eb56a378b7b2c1176787fc228d0a57172bdd5 (opens in a new tab)
- git.kernel.org/stable/c/d8ece4ced3b051e656c77180df2e69e19e24edc1 (opens in a new tab)
- git.kernel.org/stable/c/f6d45fd92f62845cbd1eb5128fd8f0ed7d0c5a42 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-3 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-4 (opens in a new tab)
- ubuntu.com/security/notices/USN-7711-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-1 (opens in a new tab)
- ubuntu.com/security/notices/USN-7704-5 (opens in a new tab)
- ubuntu.com/security/notices/USN-7712-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-7769-1 (opens in a new tab)