{"id":"CVE-2026-64556","state":"PUBLISHED","title":"perf/core: Detach event groups during remove_on_exec","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Detach event groups during remove_on_exec\n\nperf_event_remove_on_exec() removes events by calling\nperf_event_exit_event(). For top-level events, this removes the event from\nthe context with DETACH_EXIT only.\n\nThis can leave inconsistent group state when a removed event is a group\nleader and the group contains siblings without remove_on_exec. If the group\nwas active, the surviving siblings can remain active and attached to the\nremoved leader's sibling list, but are no longer represented by a valid\ngroup leader on the PMU context active lists.\n\nA later close of the removed leader uses DETACH_GROUP and can promote the\nstill-active siblings from this stale group state. The next schedule-in can\nthen add an already-linked active_list entry again, corrupting the PMU\ncontext active list.\n\nWith DEBUG_LIST enabled, this is caught as a list_add double-add in\nmerge_sched_in().\n\nFix this by detaching group relationships when remove_on_exec removes an\nevent. This preserves the existing task-exit and revoke behavior, while\nensuring surviving siblings are ungrouped before the removed event leaves\nthe context.","publishedAt":"2026-07-29T08:01:46.864Z","updatedAt":"2026-10-30T12:28:00.037Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"1d3e1102273f09180262496658e7eeed8a5a7b59","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"39358e856fb89e62e3c8d7389a2dc4ec33dbe90e","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"a2d5d3ee7b6e3953114726b1521e62123ab5b043","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"06ccef0434e98058ddae7bcebc901f93d22b7653","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"037a3c43edfb597665dd34457cd22b14692f2ba3","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/events/core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.13","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/events/core.c"]}],"references":["https://git.kernel.org/stable/c/1d3e1102273f09180262496658e7eeed8a5a7b59","https://git.kernel.org/stable/c/4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2","https://git.kernel.org/stable/c/39358e856fb89e62e3c8d7389a2dc4ec33dbe90e","https://git.kernel.org/stable/c/a2d5d3ee7b6e3953114726b1521e62123ab5b043","https://git.kernel.org/stable/c/06ccef0434e98058ddae7bcebc901f93d22b7653","https://git.kernel.org/stable/c/037a3c43edfb597665dd34457cd22b14692f2ba3"],"weaknesses":["CWE-662"],"ingestedAt":"2026-10-30T12:46:06.359Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/64xxx/CVE-2026-64556.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64556","state":"PUBLISHED","datePublished":"2026-07-29T08:01:46.864Z","dateUpdated":"2026-10-30T12:28:00.037Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-07-19T15:36:31.796Z"},"containers":{"cna":{"title":"perf/core: Detach event groups during remove_on_exec","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nperf/core: Detach event groups during remove_on_exec\n\nperf_event_remove_on_exec() removes events by calling\nperf_event_exit_event(). For top-level events, this removes the event from\nthe context with DETACH_EXIT only.\n\nThis can leave inconsistent group state when a removed event is a group\nleader and the group contains siblings without remove_on_exec. If the group\nwas active, the surviving siblings can remain active and attached to the\nremoved leader's sibling list, but are no longer represented by a valid\ngroup leader on the PMU context active lists.\n\nA later close of the removed leader uses DETACH_GROUP and can promote the\nstill-active siblings from this stale group state. The next schedule-in can\nthen add an already-linked active_list entry again, corrupting the PMU\ncontext active list.\n\nWith DEBUG_LIST enabled, this is caught as a list_add double-add in\nmerge_sched_in().\n\nFix this by detaching group relationships when remove_on_exec removes an\nevent. This preserves the existing task-exit and revoke behavior, while\nensuring surviving siblings are ungrouped before the removed event leaves\nthe context."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"1d3e1102273f09180262496658e7eeed8a5a7b59","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"39358e856fb89e62e3c8d7389a2dc4ec33dbe90e","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"a2d5d3ee7b6e3953114726b1521e62123ab5b043","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"06ccef0434e98058ddae7bcebc901f93d22b7653","versionType":"git"},{"version":"2e498d0a74e5b88a6689ae1b811f247f91ff188e","status":"affected","lessThan":"037a3c43edfb597665dd34457cd22b14692f2ba3","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/events/core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.13","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.145","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.96","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.39","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.4","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/events/core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/1d3e1102273f09180262496658e7eeed8a5a7b59"},{"url":"https://git.kernel.org/stable/c/4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2"},{"url":"https://git.kernel.org/stable/c/39358e856fb89e62e3c8d7389a2dc4ec33dbe90e"},{"url":"https://git.kernel.org/stable/c/a2d5d3ee7b6e3953114726b1521e62123ab5b043"},{"url":"https://git.kernel.org/stable/c/06ccef0434e98058ddae7bcebc901f93d22b7653"},{"url":"https://git.kernel.org/stable/c/037a3c43edfb597665dd34457cd22b14692f2ba3"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerability is triggered entirely through local syscalls — `perf_event_open(2)` to build the event group and `execve(2)`/`close(2)` to trigger the stale-group corruption. No network or physical vector is involved.\nAC:L - The attacker controls the entire deterministic sequence: create a pinned/enabled group with a `remove_on_exec` leader plus non-`remove_on_exec` siblings, exec, then close the leader. No race the attacker cannot influence is required.\nPR:L - An unprivileged user can open perf events on their own task with `exclude_kernel=1` even at the default `perf_event_paranoid=2`, requiring no capability. Basic local user access suffices.\nUI:N - The attacking process performs every step itself (open, exec, close); no action from any other user is needed.\nS:U - The corruption stays within the kernel's own security authority (PMU context list in kernel heap); it does not cross a hypervisor/IOMMU/sandbox boundary.\nC:H - Corrupting the doubly-linked active list of `perf_event` objects yields pointer manipulation over heap-embedded list nodes, which can be leveraged to read adjacent/freed kernel memory for information disclosure.\nI:H - A double `list_add`/subsequent list operations on a corrupted list provide write-what-where-style primitives against attacker-influenceable heap objects, enabling arbitrary modification and control-flow hijack.\nA:H - The list corruption reliably produces a kernel crash/oops (caught as a list_add double-add under DEBUG_LIST, silent corruption and panic otherwise), causing denial of service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:28:00.037Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.6.145"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.12.96"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"6.18.39"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.1.4"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.13","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-64556","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T15:42:33.956439Z"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-662","lang":"en","type":"CWE","description":"CWE-662 Improper Synchronization"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-19T20:48:40.883Z"}}]}}}