Linux: Use After Free
CVE-2025-39711 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 7.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists versions 3c0e4cc4f55f9a1db2a761e4ffb27c9594245888, 639f5b33fcd7c59157f29b09f6f2866eacf9279c, 1dfe73394dcfc9b049c8da0dc181c45f156a5f49 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.16% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 3c0e4cc4f55f9a1db2a761e4ffb27c9594245888 or 639f5b33fcd7c59157f29b09f6f2866eacf9279c or 1dfe73394dcfc9b049c8da0dc181c45f156a5f49 or 0c92c49fc688cfadacc47ae99b06a31237702e9e, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.103 or 6.12.44 or 6.16.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 29006e196a5661d9afc8152fa2bf8a5347ac17b4 up to, but not including, 3c0e4cc4f55f9a1db2a761e4ffb27c9594245888; 29006e196a5661d9afc8152fa2bf8a5347ac17b4 up to, but not including, 639f5b33fcd7c59157f29b09f6f2866eacf9279c; 29006e196a5661d9afc8152fa2bf8a5347ac17b4 up to, but not including, 1dfe73394dcfc9b049c8da0dc181c45f156a5f49; 29006e196a5661d9afc8152fa2bf8a5347ac17b4 up to, but not including, 0c92c49fc688cfadacc47ae99b06a31237702e9e; 6.6 | 3c0e4cc4f55f9a1db2a761e4ffb27c9594245888, 639f5b33fcd7c59157f29b09f6f2866eacf9279c, 1dfe73394dcfc9b049c8da0dc181c45f156a5f49, 0c92c49fc688cfadacc47ae99b06a31237702e9e |
| Linux | Linux Kernel | 6.6 up to, but not including, 6.6.103; 6.7 up to, but not including, 6.12.44; 6.13 up to, but not including, 6.16.4 | 6.6.103, 6.12.44, 6.16.4 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: media: ivsc: Fix crash at shutdown due to missing mei_cldev_disable() calls Both the ACE and CSI driver are missing a mei_cldev_disable() call in their remove() function. This causes the mei_cl client to stay part of the mei_device->file_list list even though its memory is freed by mei_cl_bus_dev_release() calling kfree(cldev->cl). This leads to a use-after-free when mei_vsc_remove() runs mei_stop() which first removes all mei bus devices calling mei_ace_remove() and mei_csi_remove() followed by mei_cl_bus_dev_release() and then calls mei_cl_all_disconnect() which walks over mei_device->file_list dereferecing the just freed cldev->cl. And mei_vsc_remove() it self is run at shutdown because of the platform_device_unregister(tp->pdev) in vsc_tp_shutdown() When building a kernel with KASAN this leads to the following KASAN report: [ 106.634504] ================================================================== [ 106.634623] BUG: KASAN: slab-use-after-free in mei_cl_set_disconnected (drivers/misc/mei/client.c:783) mei [ 106.634683] Read of size 4 at addr ffff88819cb62018 by task systemd-shutdow/1 [ 106.634729] [ 106.634767] Tainted: [E]=UNSIGNED_MODULE [ 106.634770] Hardware name: Dell Inc. XPS 16 9640/09CK4V, BIOS 1.12.0 02/10/2025 [ 106.634773] Call Trace: [ 106.634777] <TASK> ... [ 106.634871] kasan_report (mm/kasan/report.c:221 mm/kasan/report.c:636) [ 106.634901] mei_cl_set_disconnected (drivers/misc/mei/client.c:783) mei [ 106.634921] mei_cl_all_disconnect (drivers/misc/mei/client.c:2165 (discriminator 4)) mei [ 106.634941] mei_reset (drivers/misc/mei/init.c:163) mei ... [ 106.635042] mei_stop (drivers/misc/mei/init.c:348) mei [ 106.635062] mei_vsc_remove (drivers/misc/mei/mei_dev.h:784 drivers/misc/mei/platform-vsc.c:393) mei_vsc [ 106.635066] platform_remove (drivers/base/platform.c:1424) Add the missing mei_cldev_disable() calls so that the mei_cl gets removed from mei_device->file_list before it is freed to fix this.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
Android Runtime Use-After-Free Exploited
- 8.0 High severity
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