What is CVE-2026-64556?

CVE-2026-64556 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10, affecting Linux kernel versions from 5.13 onward and patched in 6.6.145, 6.12.96, 6.18.39 and others. CVE-2026-64556 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-64556?

CVE-2026-64556 has a CVSS score of 7.8 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

Is there a patch available for CVE-2026-64556?

Yes, CVE-2026-64556 has been patched. Fixed versions include 6.6.145, 6.12.96, 6.18.39 and others. If you are running Linux kernel 5.13 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-64556 actively exploited?

CVE-2026-64556 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-64556

High

In the Linux kernel, the following vulnerability has been resolved: perf/core: Detach event groups during remove_on_exec perf_event_remove_on_exec() removes events by calling perf_event_exit_event(). For top-level events, this removes the event from the context with DETACH_EXIT only. This can leave inconsistent group state when a removed event is a group leader and the group contains siblings without remove_on_exec. If the group was active, the surviving siblings can remain active and attached to the removed leader's sibling list, but are no longer represented by a valid group leader on the PMU context active lists. A later close of the removed leader uses DETACH_GROUP and can promote the still-active siblings from this stale group state. The next schedule-in can then add an already-linked active_list entry again, corrupting the PMU context active list. With DEBUG_LIST enabled, this is caught as a list_add double-add in merge_sched_in(). Fix this by detaching group relationships when remove_on_exec removes an event. This preserves the existing task-exit and revoke behavior, while ensuring surviving siblings are ungrouped before the removed event leaves the context.

Package Linux Kernel

Published 2026-07-29

Last modified 2026-08-17

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.8

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected versions

Linux kernel versions 5.13 and later are affected. Fixed in 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 and their respective stable series.

Affected from

≥ 5.13

Fixed in

✓ 6.6.145 6.6.x ✓ 6.12.96 6.12.x ✓ 6.18.39 6.18.x ✓ 7.1.4 7.1.x ✓ 7.2

References

5 total

Details

CVE ID CVE-2026-64556

Severity High

CVSS score 7.8 / 10

CVSS version 3.1

Published 2026-07-29

Modified 2026-08-17

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-64556?

CVE-2026-64556 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 . It affects Linux kernel versions from 5.13 onward and has been patched in 6.6.145, 6.12.96, 6.18.39 and others. CVE-2026-64556 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-64556?

CVE-2026-64556 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Is there a patch available for CVE-2026-64556?

Yes. CVE-2026-64556 has been patched. Fixed versions include 6.6.145, 6.12.96, 6.18.39 and others. If you are running Linux kernel 5.13 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-64556 actively exploited?

No. CVE-2026-64556 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.