# CVE-2025-39717: linux: In the Linux kernel, the following vulnerability has been resolved:  open_tree_attr: do not allow id-mapping changes...

CVE-2025-39717 is fixed in linux on 1 platform by DEBIAN-CVE-2025-39717 (version 6.16.5-1), released September 5, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-39717
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0016
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 5, 2025

## 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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.16.5-1 | [DEBIAN-CVE-2025-39717](https://patchblox.com/security/data/fix/linux/debian-cve-2025-39717.md) | Sep 5, 2025 |

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