CyberSecBulletin
CVE-2026-64103NVD status: Analyzed

Linux: Use After Free

Published Updated By the CyberSecBulletin desk

CVE-2026-64103 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 1412995e10c74644b47f242aea6e4f3d4180e806, a83d3e4daba40d49324cec1c51ed261e1ea48cf1, ab2266601a875982f2d2033f41e070a6d5e615e2 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.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to 1412995e10c74644b47f242aea6e4f3d4180e806 or a83d3e4daba40d49324cec1c51ed261e1ea48cf1 or ab2266601a875982f2d2033f41e070a6d5e615e2 or 309c6058622d080fe8c2fab87c30da82d834d989, whichever matches your release line, or a later version.
  2. Update Linux Kernel to 5.10.258 or 5.15.209 or 6.1.175 or 6.6.142, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux6f231dda68080759f1aed3769896e94c73099f0f up to, but not including, 1412995e10c74644b47f242aea6e4f3d4180e806; 6f231dda68080759f1aed3769896e94c73099f0f up to, but not including, a83d3e4daba40d49324cec1c51ed261e1ea48cf1; 6f231dda68080759f1aed3769896e94c73099f0f up to, but not including, ab2266601a875982f2d2033f41e070a6d5e615e2; 6f231dda68080759f1aed3769896e94c73099f0f up to, but not including, 309c6058622d080fe8c2fab87c30da82d834d989; 6f231dda68080759f1aed3769896e94c73099f0f up to, but not including, cb9e72c50e6c81a5903f27e0b397ce8525d7539b; 6f231dda68080759f1aed3769896e94c73099f0f up to, but not including, b9ff8631006233ba246828ac70409d2cb2da38d3; 6f231dda68080759f1aed3769896e94c73099f0f up to, but not including, 6d40f2f103bb30f52f3dbadbe2c3fdf274a9763c; 6f231dda68080759f1aed3769896e94c73099f0f up to, but not including, b52a8d52c3125ec9a93106ed816582368de34426; and 1 more ranges1412995e10c74644b47f242aea6e4f3d4180e806, a83d3e4daba40d49324cec1c51ed261e1ea48cf1, ab2266601a875982f2d2033f41e070a6d5e615e2, 309c6058622d080fe8c2fab87c30da82d834d989, cb9e72c50e6c81a5903f27e0b397ce8525d7539b, b9ff8631006233ba246828ac70409d2cb2da38d3
LinuxLinux Kernel3.0.1 up to, but not including, 5.10.258; 5.11 up to, but not including, 5.15.209; 5.16 up to, but not including, 6.1.175; 6.2 up to, but not including, 6.6.142; 6.7 up to, but not including, 6.12.92; 6.13 up to, but not including, 6.18.34; 6.19 up to, but not including, 7.0.11; 3.0; and 1 more ranges5.10.258, 5.15.209, 6.1.175, 6.6.142, 6.12.92, 6.18.34

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: scsi: isci: Fix use-after-free in device removal path The ISCI completion tasklet is initialized in isci_host_alloc() (drivers/scsi/isci/init.c:496) and scheduled from both MSI-X and legacy interrupt handlers (drivers/scsi/isci/host.c:223,613). isci_host_deinit() stops the controller and waits for stop completion, but it never kills completion_tasklet before teardown continues. A top-of-function tasklet_kill() is not sufficient here: interrupts are only disabled when isci_host_stop_complete() runs, so until wait_for_stop() returns the IRQ handlers can still requeue the tasklet. The tasklet callback also re-enables interrupts after draining completions, so killing the tasklet before the source is quiesced leaves the same race open. Once wait_for_stop() returns, no further IRQ-driven scheduling can occur. Kill completion_tasklet there so teardown cannot race a queued tasklet running on a dead ihost. On remove or unload, the stale callback can otherwise dereference ihost and touch ihost->smu_registers after the host lifetime ends. A UML + KASAN analogue reproduced the failure class both with no tasklet_kill() and with tasklet_kill() placed before source quiesce, and stayed clean once the kill happened after quiescing the scheduling source. This mirrors commit f6ab594672d4 ("scsi: aic94xx: fix use-after-free in device removal path"), but ISCI needs the kill after wait_for_stop().

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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