Linux: Use After Free
CVE-2026-64421 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 d22fb719654bfde6f682c9f14629f5f9534175b7, ba2aa5d325270cd965c44458c5ff5ab555e6af51, ef382a6baf0a95cf199fdf6bba2fd08e58b0a249 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 0.13% 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 d22fb719654bfde6f682c9f14629f5f9534175b7 or ba2aa5d325270cd965c44458c5ff5ab555e6af51 or ef382a6baf0a95cf199fdf6bba2fd08e58b0a249 or c12a5b2261351cd3b03921ce4720332ff5184b50, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.145 or 6.12.97 or 6.18.40 or 7.1.4, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | cf21f328fcafacf4f96e7a30ef9dceede1076378 up to, but not including, d22fb719654bfde6f682c9f14629f5f9534175b7; cf21f328fcafacf4f96e7a30ef9dceede1076378 up to, but not including, ba2aa5d325270cd965c44458c5ff5ab555e6af51; cf21f328fcafacf4f96e7a30ef9dceede1076378 up to, but not including, ef382a6baf0a95cf199fdf6bba2fd08e58b0a249; cf21f328fcafacf4f96e7a30ef9dceede1076378 up to, but not including, c12a5b2261351cd3b03921ce4720332ff5184b50; cf21f328fcafacf4f96e7a30ef9dceede1076378 up to, but not including, b670bf89824ede5d07d20bb9bfbafb754846081d; 6.4 | d22fb719654bfde6f682c9f14629f5f9534175b7, ba2aa5d325270cd965c44458c5ff5ab555e6af51, ef382a6baf0a95cf199fdf6bba2fd08e58b0a249, c12a5b2261351cd3b03921ce4720332ff5184b50, b670bf89824ede5d07d20bb9bfbafb754846081d |
| Linux | Linux Kernel | 6.4 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.97; 6.13 up to, but not including, 6.18.40; 6.19 up to, but not including, 7.1.4 | 6.6.145, 6.12.97, 6.18.40, 7.1.4 |
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.
Official description
In the Linux kernel, the following vulnerability has been resolved: media: nxp: imx8-isi: Fix use-after-free on remove KASAN reports a slab-use-after-free in __media_entity_remove_link() during rmmod of imx8_isi: BUG: KASAN: slab-use-after-free in __media_entity_remove_link+0x608/0x650 Read of size 2 at addr ffff0000d47cb02a by task rmmod/724 Call trace: __media_entity_remove_link+0x608/0x650 __media_entity_remove_links+0x78/0x144 __media_device_unregister_entity+0x150/0x280 media_device_unregister_entity+0x48/0x68 v4l2_device_unregister_subdev+0x158/0x300 v4l2_async_unbind_subdev_one+0x22c/0x358 v4l2_async_nf_unbind_all_subdevs+0xfc/0x1c0 v4l2_async_nf_unregister+0x5c/0x14c mxc_isi_remove+0x124/0x2a0 [imx8_isi] Allocated by task 249: __kmalloc_noprof+0x27c/0x690 mxc_isi_crossbar_init+0x22c/0x560 [imx8_isi] Freed by task 724: kfree+0x1e4/0x5b0 mxc_isi_crossbar_cleanup+0x34/0x80 [imx8_isi] mxc_isi_remove+0x11c/0x2a0 [imx8_isi] The problem is that mxc_isi_remove() calls mxc_isi_crossbar_cleanup() before mxc_isi_v4l2_cleanup(). The crossbar cleanup frees the media entity pads, but the subsequent v4l2 cleanup still tries to remove media links that reference those pads. Fix this by calling mxc_isi_v4l2_cleanup() before mxc_isi_crossbar_cleanup() to ensure all media entities are properly unregistered while the pads are still valid.
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
- git.kernel.org/stable/c/b670bf89824ede5d07d20bb9bfbafb754846081d
- git.kernel.org/stable/c/ba2aa5d325270cd965c44458c5ff5ab555e6af51
- git.kernel.org/stable/c/c12a5b2261351cd3b03921ce4720332ff5184b50
- git.kernel.org/stable/c/d22fb719654bfde6f682c9f14629f5f9534175b7
- git.kernel.org/stable/c/ef382a6baf0a95cf199fdf6bba2fd08e58b0a249
Recent Use After Free vulnerabilities
- 9.8 Critical severity
- 7.8 High severity
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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