CVE-2026-64556: Linux kernel · perf/core: Detach event groups during remove_on_exec
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 29 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| 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
- git.kernel.org/stable/c/4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2 (opens in a new tab)
- git.kernel.org/stable/c/39358e856fb89e62e3c8d7389a2dc4ec33dbe90e (opens in a new tab)
- git.kernel.org/stable/c/a2d5d3ee7b6e3953114726b1521e62123ab5b043 (opens in a new tab)
- git.kernel.org/stable/c/06ccef0434e98058ddae7bcebc901f93d22b7653 (opens in a new tab)
- git.kernel.org/stable/c/037a3c43edfb597665dd34457cd22b14692f2ba3 (opens in a new tab)