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VulnerabilityPublished Updated

CVE-2026-64556: Linux kernel · perf/core: Detach event groups during remove_on_exec

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in a2d5d3ee7b6e3953114726b1521e62123ab5b043 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in a2d5d3ee7b6e3953114726b1521e62123ab5b043, 39358e856fb89e62e3c8d7389a2dc4ec33dbe90e, 037a3c43edfb597665dd34457cd22b14692f2ba3 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Jul 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 2e498d0a74e5b88a6689ae1b811f247f91ff188e, < a2d5d3ee7b6e3953114726b1521e62123ab5b043
Fixed in
  • a2d5d3ee7b6e3953114726b1521e62123ab5b043
LinuxLinuxAffected
  • ≥ 2e498d0a74e5b88a6689ae1b811f247f91ff188e, < 39358e856fb89e62e3c8d7389a2dc4ec33dbe90e
Fixed in
  • 39358e856fb89e62e3c8d7389a2dc4ec33dbe90e
LinuxLinuxAffected
  • ≥ 2e498d0a74e5b88a6689ae1b811f247f91ff188e, < 037a3c43edfb597665dd34457cd22b14692f2ba3
Fixed in
  • 037a3c43edfb597665dd34457cd22b14692f2ba3
LinuxLinuxAffected
  • ≥ 2e498d0a74e5b88a6689ae1b811f247f91ff188e, < 06ccef0434e98058ddae7bcebc901f93d22b7653
Fixed in
  • 06ccef0434e98058ddae7bcebc901f93d22b7653
LinuxLinuxAffected
  • ≥ 2e498d0a74e5b88a6689ae1b811f247f91ff188e, < 4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2
Fixed in
  • 4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2
LinuxLinuxAffected
  • =5.13
Fixed in–

Description

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.

References

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