CyberSecBulletin
CVE-2026-64363NVD status: Analyzed

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-64363 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 89ef67359672bf4cd6921524e39f61648fe38c0f, 3d30a0bb0e79621ae921b487835c56198adfafa3, 37a52c61d4f78153c38ae1f7491dfcc8ac828dcf 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 0.17% 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 89ef67359672bf4cd6921524e39f61648fe38c0f or 3d30a0bb0e79621ae921b487835c56198adfafa3 or 37a52c61d4f78153c38ae1f7491dfcc8ac828dcf or 05e3decc55d1deca9410e0eb36466651fcbe57a5, 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
LinuxLinux9a4a5574ce427c364d81746fc7fb82d86b5f1a7e up to, but not including, 89ef67359672bf4cd6921524e39f61648fe38c0f; 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e up to, but not including, 3d30a0bb0e79621ae921b487835c56198adfafa3; 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e up to, but not including, 37a52c61d4f78153c38ae1f7491dfcc8ac828dcf; 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e up to, but not including, 05e3decc55d1deca9410e0eb36466651fcbe57a5; 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e up to, but not including, 3755f6e25776b8b12ddf062f9b573f05090e4034; 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e up to, but not including, b363d964ca829c1761c9f04188dfa28f90b0f2d4; 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e up to, but not including, 6b0838e86da88b1d3bff86f19761ff25af73eaca; 9a4a5574ce427c364d81746fc7fb82d86b5f1a7e up to, but not including, 75fe87e19d8aff81eb2c64d15d244ab8da4de945; and 1 more ranges89ef67359672bf4cd6921524e39f61648fe38c0f, 3d30a0bb0e79621ae921b487835c56198adfafa3, 37a52c61d4f78153c38ae1f7491dfcc8ac828dcf, 05e3decc55d1deca9410e0eb36466651fcbe57a5, 3755f6e25776b8b12ddf062f9b573f05090e4034, b363d964ca829c1761c9f04188dfa28f90b0f2d4
LinuxLinux Kernel3.10 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, 6.12.97; 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, 6.12.97, 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: HID: appleir: fix UAF on pending key_up_timer in remove() appleir_remove() runs hid_hw_stop() before timer_delete_sync(). hid_hw_stop() synchronously unregisters the HID input device via hid_disconnect() -> hidinput_disconnect() -> input_unregister_device(), which drops the last reference and frees the underlying input_dev when no userspace handle holds it open. key_up_tick() reads appleir->input_dev and calls input_report_key() / input_sync() on it. The timer is armed from appleir_raw_event() with a HZ/8 (~125 ms) timeout on every keydown and key-repeat report. If a key was pressed shortly before the device is disconnected, the timer can fire after hid_hw_stop() has freed input_dev but before the teardown drains it. A simple reorder is not sufficient. Putting the timer drain first still leaves a window where a USB URB completion (raw_event) running during hid_hw_stop() can call mod_timer() and re-arm the timer, which then fires after hidinput_disconnect() has freed input_dev. The same URB-completion window also lets raw_event() reach key_up(), key_down() and battery_flat() directly, all of which dereference appleir->input_dev. Introduce a 'removing' flag on struct appleir, gated by the existing spinlock. appleir_remove() sets the flag under the lock and then shuts down the timer with timer_shutdown_sync(), which both drains any in-flight callback and permanently disables further mod_timer() calls. appleir_raw_event() and key_up_tick() bail out early if the flag is set, so no path can arm or run the timer, or dereference appleir->input_dev, after remove() has started tearing down. The keyrepeat and flatbattery branches of appleir_raw_event() previously called into the input layer without holding the spinlock; take it now so the flag check is well-defined. This incidentally closes a pre-existing read-side race on appleir->current_key in the keyrepeat branch. This bug is structurally a sibling of commit 4db2af929279 ("HID: appletb-kbd: fix UAF in inactivity-timer cleanup path") and has been present since the driver was introduced.

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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