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VulnerabilityPublished Updated

CVE-2025-39717: Linux kernel · open_tree_attr: do not allow id-mapping changes without OPEN_TREE_CLONE

Affects Linux kernelSource GCVE Database

0

Not known to be exploited · CVSS 7.8 High.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 4% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 Sep 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

Affected software

ProductAffectedFixed in
Ubuntu 24.04 LTSlinux-azure-6.11pkg:deb/ubuntu/linux-azure-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1008.8~24.04.1 – 6.11.0-1018.18~24.04.1
7 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-gcp-6.11pkg:deb/ubuntu/linux-gcp-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1006.6~24.04.2 – 6.11.0-1017.17~24.04.1
7 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-hwe-6.11pkg:deb/ubuntu/linux-hwe-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-17.17~24.04.2 – 6.11.0-29.29~24.04.1
8 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-intelpkg:deb/ubuntu/linux-intel?arch=source&distro=nobleOther threatsAffected
  • =6.8.0-1005.12
  • =6.8.0-1006.13
  • =6.8.0-1007.14
Fixed in–
Ubuntu 24.04 LTSlinux-lowlatency-hwe-6.11pkg:deb/ubuntu/linux-lowlatency-hwe-6.11?arch=source&distro=nobleOther threatsAffected
  • 6.11.0-1009.10~24.04.1 – 6.11.0-1016.17~24.04.1
7 affected builds
Fixed in–
Ubuntu 24.04 LTSlinux-oem-6.8pkg:deb/ubuntu/linux-oem-6.8?arch=source&distro=nobleOther threatsAffected
  • 6.8.0-1003.3 – 6.8.0-1032.32
26 affected builds
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: open_tree_attr: do not allow id-mapping changes without OPEN_TREE_CLONE As described in commit 7a54947e727b ('Merge patch series "fs: allow changing idmappings"'), open_tree_attr(2) was necessary in order to allow for a detached mount to be created and have its idmappings changed without the risk of any racing threads operating on it. For this reason, mount_setattr(2) still does not allow for id-mappings to be changed. However, there was a bug in commit 2462651ffa76 ("fs: allow changing idmappings") which allowed users to bypass this restriction by calling open_tree_attr(2) *without* OPEN_TREE_CLONE. can_idmap_mount() prevented this bug from allowing an attached mountpoint's id-mapping from being modified (thanks to an is_anon_ns() check), but this still allows for detached (but visible) mounts to have their be id-mapping changed. This risks the same UAF and locking issues as described in the merge commit, and was likely unintentional.

References

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