CyberSecBulletin
CVE-2026-64455NVD status: Analyzed

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-64455 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 fe7a0f4be283b40dd592540027279735120d0d6f, 5ec61fbef9ec5635c492ae63dfb5d13f2bdf1023, f3e409476ad0703c54c14f245e4e143c8124e1bd 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 0.14% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to fe7a0f4be283b40dd592540027279735120d0d6f or 5ec61fbef9ec5635c492ae63dfb5d13f2bdf1023 or f3e409476ad0703c54c14f245e4e143c8124e1bd or 6c82f88bc7a8458d5c60f9b354c4d32d233f0cac, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.261 or 5.15.212 or 6.1.178 or 6.6.145, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux66e3e591891da9899a8990792da080432531ffd4 up to, but not including, fe7a0f4be283b40dd592540027279735120d0d6f; 66e3e591891da9899a8990792da080432531ffd4 up to, but not including, 5ec61fbef9ec5635c492ae63dfb5d13f2bdf1023; 66e3e591891da9899a8990792da080432531ffd4 up to, but not including, f3e409476ad0703c54c14f245e4e143c8124e1bd; 66e3e591891da9899a8990792da080432531ffd4 up to, but not including, 6c82f88bc7a8458d5c60f9b354c4d32d233f0cac; 66e3e591891da9899a8990792da080432531ffd4 up to, but not including, 3ad5fbcced4e9c2b0fee3c1b76289a147fc35b89; 66e3e591891da9899a8990792da080432531ffd4 up to, but not including, 2a52d55c86a429dac47886b8424e67f90b001e67; 66e3e591891da9899a8990792da080432531ffd4 up to, but not including, 8f50613bff228272577893aa10a346a2f3063e49; 66e3e591891da9899a8990792da080432531ffd4 up to, but not including, abf76d3239dee97b66e7241ad04811f1ce562e28; and 1 more rangesfe7a0f4be283b40dd592540027279735120d0d6f, 5ec61fbef9ec5635c492ae63dfb5d13f2bdf1023, f3e409476ad0703c54c14f245e4e143c8124e1bd, 6c82f88bc7a8458d5c60f9b354c4d32d233f0cac, 3ad5fbcced4e9c2b0fee3c1b76289a147fc35b89, 2a52d55c86a429dac47886b8424e67f90b001e67
LinuxLinux Kernel4.1 up to, but not including, 5.10.261; 5.11 up to, but not including, 5.15.212; 5.16 up to, but not including, 6.1.178; 6.2 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; 7.25.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, 6.18.39

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: chaoskey: Fix slab-use-after-free in chaoskey_release() The chaoskey driver has a use-after-free bug in its release routine. If the user closes the device file after the USB device has been unplugged, a debugging log statement will try to access the usb_interface structure after it has been deallocated: BUG: KASAN: slab-use-after-free in dev_driver_string (drivers/base/core.c:2406) Read of size 8 at addr ffff888168e8a0b8 by task chaoskey_raw_re/10106 Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:94 lib/dump_stack.c:120) print_report (mm/kasan/report.c:378 mm/kasan/report.c:482) kasan_report (mm/kasan/report.c:595) dev_driver_string (drivers/base/core.c:2406) __dynamic_dev_dbg (lib/dynamic_debug.c:906) chaoskey_release (drivers/usb/misc/chaoskey.c:323) __fput (fs/file_table.c:510) fput_close_sync (fs/file_table.c:615) __x64_sys_close (fs/open.c:1507 fs/open.c:1492 fs/open.c:1492) do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) The driver's last reference to the interface structure is dropped in the chaoskey_free() routine, so the code must not use the interface -- even in a debugging statement -- after that routine returns. (Exception: If we know that another reference is held by someone else, such as the device core while the disconnect routine runs, there's no problem. Thanks to Johan Hovold for pointing this out.) Since the bad access is part of an unimportant debugging statement, we can fix the problem simply by removing the whole statement.

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.

More Use After Free vulnerabilities (CWE-416)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Use After Free vulnerabilities

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