{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-64556", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-07-19T15:36:31.796Z", "datePublished": "2026-07-29T08:01:46.864Z", "dateUpdated": "2026-08-17T04:57:34.489Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-17T04:57:34.489Z" }, "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." } ], "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." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/events/core.c" ], "versions": [ { "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e", "lessThan": "4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2", "status": "affected", "versionType": "git" }, { "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e", "lessThan": "39358e856fb89e62e3c8d7389a2dc4ec33dbe90e", "status": "affected", "versionType": "git" }, { "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e", "lessThan": "a2d5d3ee7b6e3953114726b1521e62123ab5b043", "status": "affected", "versionType": "git" }, { "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e", "lessThan": "06ccef0434e98058ddae7bcebc901f93d22b7653", "status": "affected", "versionType": "git" }, { "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e", "lessThan": "037a3c43edfb597665dd34457cd22b14692f2ba3", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "kernel/events/core.c" ], "versions": [ { "version": "5.13", "status": "affected" }, { "version": "0", "lessThan": "5.13", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.145", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.96", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.39", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1.4", "lessThanOrEqual": "7.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "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" } ] } ] } ], "references": [ { "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" } ], "title": "perf/core: Detach event groups during remove_on_exec", "x_generator": { "engine": "bippy-1.2.0" } } } }