Vulnerability-Lookup

GHSA-MPX2-CMQF-859J

Vulnerability from github – Published: 2026-07-29 09:31 – Updated: 2026-07-30 06:32

Details

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.

Severity

7.8 (High)


                  
                    CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-64556"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-29T09:16:30Z",
    "severity": "HIGH"
  },
  "details": "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\u0027s 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.",
  "id": "GHSA-mpx2-cmqf-859j",
  "modified": "2026-07-30T06:32:35Z",
  "published": "2026-07-29T09:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64556"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/037a3c43edfb597665dd34457cd22b14692f2ba3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/06ccef0434e98058ddae7bcebc901f93d22b7653"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/39358e856fb89e62e3c8d7389a2dc4ec33dbe90e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a2d5d3ee7b6e3953114726b1521e62123ab5b043"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-64556 (GCVE-0-2026-64556)

Vulnerability from cvelistv5 – Published: 2026-07-29 08:01 – Updated: 2026-08-17 04:57

Title

perf/core: Detach event groups during remove_on_exec

Summary

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.

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Assigner

Linux mitre root

References

5 references

URL	Tags
https://git.kernel.org/stable/c/4cdb1b3ab96eb1b7e…
https://git.kernel.org/stable/c/39358e856fb89e62e…
https://git.kernel.org/stable/c/a2d5d3ee7b6e39531…
https://git.kernel.org/stable/c/06ccef0434e98058d…
https://git.kernel.org/stable/c/037a3c43edfb59766…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 2e498d0a74e5b88a6689ae1b811f247f91ff188e , < 4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2 (git) Affected: 2e498d0a74e5b88a6689ae1b811f247f91ff188e , < 39358e856fb89e62e3c8d7389a2dc4ec33dbe90e (git) Affected: 2e498d0a74e5b88a6689ae1b811f247f91ff188e , < a2d5d3ee7b6e3953114726b1521e62123ab5b043 (git) Affected: 2e498d0a74e5b88a6689ae1b811f247f91ff188e , < 06ccef0434e98058ddae7bcebc901f93d22b7653 (git) Affected: 2e498d0a74e5b88a6689ae1b811f247f91ff188e , < 037a3c43edfb597665dd34457cd22b14692f2ba3 (git)
Linux	Linux	Affected: 5.13 Unaffected: 0 , < 5.13 (semver) Unaffected: 6.6.145 , ≤ 6.6.* (semver) Unaffected: 6.12.96 , ≤ 6.12.* (semver) Unaffected: 6.18.39 , ≤ 6.18.* (semver) Unaffected: 7.1.4 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/events/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4cdb1b3ab96eb1b7eb70bc5c82fede334bd60df2",
              "status": "affected",
              "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e",
              "versionType": "git"
            },
            {
              "lessThan": "39358e856fb89e62e3c8d7389a2dc4ec33dbe90e",
              "status": "affected",
              "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e",
              "versionType": "git"
            },
            {
              "lessThan": "a2d5d3ee7b6e3953114726b1521e62123ab5b043",
              "status": "affected",
              "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e",
              "versionType": "git"
            },
            {
              "lessThan": "06ccef0434e98058ddae7bcebc901f93d22b7653",
              "status": "affected",
              "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e",
              "versionType": "git"
            },
            {
              "lessThan": "037a3c43edfb597665dd34457cd22b14692f2ba3",
              "status": "affected",
              "version": "2e498d0a74e5b88a6689ae1b811f247f91ff188e",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/events/core.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.13"
            },
            {
              "lessThan": "5.13",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.145",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.96",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.39",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1.4",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "5.13",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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\u0027s 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": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The vulnerability is triggered entirely through local syscalls \u2014 `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\u0027s 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": {
        "dateUpdated": "2026-08-17T04:57:34.489Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "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"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64556",
    "datePublished": "2026-07-29T08:01:46.864Z",
    "dateReserved": "2026-07-19T15:36:31.796Z",
    "dateUpdated": "2026-08-17T04:57:34.489Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.