Linux: Use After Free
CVE-2026-64348 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 b0d00d077f9738d215af9b50c74dffab7a1de19f, ab12316c4639237cc9d50c80a0c6240f11fbba3f, be5004395dfd0b6ec310db359f887fa396fd0dd2 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 b0d00d077f9738d215af9b50c74dffab7a1de19f or ab12316c4639237cc9d50c80a0c6240f11fbba3f or be5004395dfd0b6ec310db359f887fa396fd0dd2 or 8890699eea19027ef6e4f9cbcf27cba5e789793f, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.261 or 6.6.145 or 6.12.96 or 6.18.39, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 8de98402652c01839ae321be6cb3054cf5735d83 up to, but not including, b0d00d077f9738d215af9b50c74dffab7a1de19f; 8de98402652c01839ae321be6cb3054cf5735d83 up to, but not including, ab12316c4639237cc9d50c80a0c6240f11fbba3f; 8de98402652c01839ae321be6cb3054cf5735d83 up to, but not including, be5004395dfd0b6ec310db359f887fa396fd0dd2; 8de98402652c01839ae321be6cb3054cf5735d83 up to, but not including, 8890699eea19027ef6e4f9cbcf27cba5e789793f; 8de98402652c01839ae321be6cb3054cf5735d83 up to, but not including, 6bc17a78a05671d303820224fb37ca339c1dc2cb; 8de98402652c01839ae321be6cb3054cf5735d83 up to, but not including, 4bb88aee6b868cbf73bf453f62497802f5fe4769; 8de98402652c01839ae321be6cb3054cf5735d83 up to, but not including, b9399d25fbb34a05bbe76eeedd730f62ff2670e9; 2.6.15 | b0d00d077f9738d215af9b50c74dffab7a1de19f, ab12316c4639237cc9d50c80a0c6240f11fbba3f, be5004395dfd0b6ec310db359f887fa396fd0dd2, 8890699eea19027ef6e4f9cbcf27cba5e789793f, 6bc17a78a05671d303820224fb37ca339c1dc2cb, 4bb88aee6b868cbf73bf453f62497802f5fe4769 |
| Linux | Linux Kernel | 2.6.15.1 up to, but not including, 5.10.261; 5.11 up to, but not including, 6.6.145; 6.7 up to, but not including, 6.12.96; 6.13 up to, but not including, 6.18.39; 6.19 up to, but not including, 7.1.4; 2.6.15; 7.2 | 5.10.261, 6.6.145, 6.12.96, 6.18.39, 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: usb: free iso schedules on failed submit EHCI and FOTG210 isochronous submits build an ehci_iso_sched before linking the URB to the endpoint queue, and keep the staged schedule in urb->hcpriv until iso_stream_schedule() and the link helpers consume it. If the controller is no longer accessible, or usb_hcd_link_urb_to_ep() fails, submit jumps to done_not_linked before that handoff happens and leaks the staged schedule still attached to urb->hcpriv. Free the staged schedule from done_not_linked when submit fails before the URB is linked and clear urb->hcpriv after the free. The bug was first flagged by an experimental analysis tool we are developing for kernel memory-management bugs while analyzing v6.13-rc1. The tool is still under development and is not yet publicly available. Manual inspection confirms that the bug is still present in v7.1.1. An x86_64 allyesconfig build showed no new warnings. As we do not have an EHCI host controller with a USB isochronous device to test with, no runtime testing was able to be performed.
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.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/4bb88aee6b868cbf73bf453f62497802f5fe4769
- git.kernel.org/stable/c/6bc17a78a05671d303820224fb37ca339c1dc2cb
- git.kernel.org/stable/c/8890699eea19027ef6e4f9cbcf27cba5e789793f
- git.kernel.org/stable/c/b0d00d077f9738d215af9b50c74dffab7a1de19f
- git.kernel.org/stable/c/b9399d25fbb34a05bbe76eeedd730f62ff2670e9
- git.kernel.org/stable/c/be5004395dfd0b6ec310db359f887fa396fd0dd2
Other references
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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