Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: perf/core: Detach event groups during remove_on_exec perf_event_remove_on_exec()… (CVE-2026-64556)
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.
AI Analysis
Technical Summary
The Linux kernel vulnerability (CVE-2026-64556) involves the perf subsystem's handling of event groups during the remove_on_exec operation. Specifically, perf_event_remove_on_exec() removes events by calling perf_event_exit_event(), but for top-level events, it only removes the event with DETACH_EXIT, leaving sibling events in an inconsistent state if the removed event was a group leader. This can cause surviving siblings to remain active and linked to a stale group leader, corrupting the PMU context active list upon subsequent scheduling. The fix detaches group relationships properly during remove_on_exec to maintain consistent group state and prevent list corruption.
Potential Impact
The vulnerability can lead to corruption of the PMU context active list, which affects the kernel's performance monitoring subsystem. This corruption can impact system stability and reliability, potentially causing denial of service or other integrity and availability issues. The CVSS vector indicates high impact on confidentiality, integrity, and availability, though no known exploits are reported in the wild.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to properly detach event groups during the remove_on_exec operation, resolving the inconsistent group state issue. Users should apply the official kernel updates that include this fix once available. Patch status is not explicitly confirmed in the provided data; check the vendor or kernel mailing lists for the official patch and update guidance.
Linux hwe edge: In the Linux kernel, the following vulnerability has been resolved: perf/core: Detach event groups during remove_on_exec perf_event_remove_on_exec()… (CVE-2026-64556)
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.
CVSS v3.1
Score 7.8high
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel vulnerability (CVE-2026-64556) involves the perf subsystem's handling of event groups during the remove_on_exec operation. Specifically, perf_event_remove_on_exec() removes events by calling perf_event_exit_event(), but for top-level events, it only removes the event with DETACH_EXIT, leaving sibling events in an inconsistent state if the removed event was a group leader. This can cause surviving siblings to remain active and linked to a stale group leader, corrupting the PMU context active list upon subsequent scheduling. The fix detaches group relationships properly during remove_on_exec to maintain consistent group state and prevent list corruption.
Potential Impact
The vulnerability can lead to corruption of the PMU context active list, which affects the kernel's performance monitoring subsystem. This corruption can impact system stability and reliability, potentially causing denial of service or other integrity and availability issues. The CVSS vector indicates high impact on confidentiality, integrity, and availability, though no known exploits are reported in the wild.
Mitigation Recommendations
A fix has been implemented in the Linux kernel to properly detach event groups during the remove_on_exec operation, resolving the inconsistent group state issue. Users should apply the official kernel updates that include this fix once available. Patch status is not explicitly confirmed in the provided data; check the vendor or kernel mailing lists for the official patch and update guidance.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-mpx2-cmqf-859j
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-64556"]
- Ecosystems
- []
- Database Specific Severity
- HIGH
- Cvss Version
- 3.1
Threat ID: 6a6b72cf9c2644c7f8476898
Added to database: 07/30/2026, 15:50:39 UTC
Last enriched: 07/30/2026, 19:37:39 UTC
Last updated: 07/31/2026, 21:28:51 UTC
Views: 2
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