Vulnerability-Lookup

GHSA-G336-8H5F-6M63

Vulnerability from github – Published: 2026-08-15 06:32 – Updated: 2026-08-17 06:33

Details

In the Linux kernel, the following vulnerability has been resolved:

bpf: Take mmap_lock in zap_pages()

zap_vma_range() requires the owning mm's mmap_lock to be held.

Taking mmap_read_lock under arena->lock would AB-BA against arena_vm_close() and arena_map_mmap(), both of which run with mmap_write_lock held and then acquire arena->lock. Instead drop arena->lock, mmget_not_zero() the vma's mm, take mmap_read_lock, and re-resolve the vma via find_vma() since it may have been unmapped or replaced while waiting.

Track processed vmls with a per-call generation in vml->zap_gen and serialize zap_pages() callers with a new arena->zap_mutex so concurrent callers on different uaddr ranges do not mark each other's vmls processed before the zap is done.

Severity

7.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-74354"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-08-15T06:22:36Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Take mmap_lock in zap_pages()\n\nzap_vma_range() requires the owning mm\u0027s mmap_lock to be held.\n\nTaking mmap_read_lock under arena-\u003elock would AB-BA against\narena_vm_close() and arena_map_mmap(), both of which run with\nmmap_write_lock held and then acquire arena-\u003elock. Instead drop\narena-\u003elock, mmget_not_zero() the vma\u0027s mm, take mmap_read_lock, and\nre-resolve the vma via find_vma() since it may have been unmapped or\nreplaced while waiting.\n\nTrack processed vmls with a per-call generation in vml-\u003ezap_gen and\nserialize zap_pages() callers with a new arena-\u003ezap_mutex so\nconcurrent callers on different uaddr ranges do not mark each other\u0027s\nvmls processed before the zap is done.",
  "id": "GHSA-g336-8h5f-6m63",
  "modified": "2026-08-17T06:33:40Z",
  "published": "2026-08-15T06:32:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74354"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/36b1d997866f6083d33934983aa2ce0a184ed642"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/80b89d0226a05e8b67969de99c31b51fcd54f76a"
    }
  ],
  "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-2026-74354 (GCVE-0-2026-74354)

Vulnerability from cvelistv5 – Published: 2026-08-15 05:58 – Updated: 2026-08-17 05:46

Title

bpf: Take mmap_lock in zap_pages()

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: Take mmap_lock in zap_pages() zap_vma_range() requires the owning mm's mmap_lock to be held. Taking mmap_read_lock under arena->lock would AB-BA against arena_vm_close() and arena_map_mmap(), both of which run with mmap_write_lock held and then acquire arena->lock. Instead drop arena->lock, mmget_not_zero() the vma's mm, take mmap_read_lock, and re-resolve the vma via find_vma() since it may have been unmapped or replaced while waiting. Track processed vmls with a per-call generation in vml->zap_gen and serialize zap_pages() callers with a new arena->zap_mutex so concurrent callers on different uaddr ranges do not mark each other's vmls processed before the zap is done.

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

2 references

URL	Tags
https://git.kernel.org/stable/c/36b1d997866f6083d…
https://git.kernel.org/stable/c/80b89d0226a05e8b6…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 317460317a02a1af512697e6e964298dedd8a163 , < 36b1d997866f6083d33934983aa2ce0a184ed642 (git) Affected: 317460317a02a1af512697e6e964298dedd8a163 , < 80b89d0226a05e8b67969de99c31b51fcd54f76a (git)
Linux	Linux	Affected: 6.9 Unaffected: 0 , < 6.9 (semver) Unaffected: 7.1.5 , ≤ 7.1.* (semver) Unaffected: 7.2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/arena.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "36b1d997866f6083d33934983aa2ce0a184ed642",
              "status": "affected",
              "version": "317460317a02a1af512697e6e964298dedd8a163",
              "versionType": "git"
            },
            {
              "lessThan": "80b89d0226a05e8b67969de99c31b51fcd54f76a",
              "status": "affected",
              "version": "317460317a02a1af512697e6e964298dedd8a163",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/arena.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.9"
            },
            {
              "lessThan": "6.9",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "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": "7.1.5",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2",
                  "versionStartIncluding": "6.9",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Take mmap_lock in zap_pages()\n\nzap_vma_range() requires the owning mm\u0027s mmap_lock to be held.\n\nTaking mmap_read_lock under arena-\u003elock would AB-BA against\narena_vm_close() and arena_map_mmap(), both of which run with\nmmap_write_lock held and then acquire arena-\u003elock. Instead drop\narena-\u003elock, mmget_not_zero() the vma\u0027s mm, take mmap_read_lock, and\nre-resolve the vma via find_vma() since it may have been unmapped or\nreplaced while waiting.\n\nTrack processed vmls with a per-call generation in vml-\u003ezap_gen and\nserialize zap_pages() callers with a new arena-\u003ezap_mutex so\nconcurrent callers on different uaddr ranges do not mark each other\u0027s\nvmls processed before the zap is done."
        }
      ],
      "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 flaw is reached only via local bpf(2) syscalls: creating a BPF_MAP_TYPE_ARENA, loading a JIT BPF program using bpf_arena_free_pages(), mmap()ing the arena, and executing that program, which calls zap_pages() and zap_vma_range() without mmap_lock.\nAC:L - Exploitation requires racing page unmap with concurrent VMA teardown; the attacker controls both sides by running bpf_arena_free_pages() from BPF while another thread or process concurrently munmap()s or remaps the same arena mapping.\nPR:L - Arena map creation requires CAP_BPF and verifier-enforced CAP_BPF plus CAP_PERFMON (bpf_allow_ptr_leaks), not init-namespace root; these capabilities are obtainable by an unprivileged user via user namespaces or perf-group membership on typical systems.\nUI:N - No victim interaction is required beyond the attacker loading their own BPF program and mmaping their own arena; triggering the race is fully automated once those attacker-controlled setup steps are done.\nS:U - Impact is confined to kernel memory management and process address spaces on the host; it does not cross a VM, container, or IOMMU security boundary into a separate authority such as a hypervisor host escape.\nC:H - Calling zap_vma_range() without mmap_lock races with munmap and page faults, enabling stale VMA use, page-table corruption, and use-after-free conditions that can be leveraged for arbitrary kernel or cross-process memory disclosure.\nI:H - Unsynchronized PTE zapping and rmap updates can corrupt page tables and VMA metadata, providing memory corruption primitives that can be developed into arbitrary kernel writes and control-flow hijacking.\nA:H - The mmap_lock violation can cause kernel oopses, panics, or hung memory management from inconsistent page tables and invalid VMA access during concurrent unmap operations."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:46:14.991Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/36b1d997866f6083d33934983aa2ce0a184ed642"
        },
        {
          "url": "https://git.kernel.org/stable/c/80b89d0226a05e8b67969de99c31b51fcd54f76a"
        }
      ],
      "title": "bpf: Take mmap_lock in zap_pages()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-74354",
    "datePublished": "2026-08-15T05:58:40.067Z",
    "dateReserved": "2026-08-15T05:44:03.887Z",
    "dateUpdated": "2026-08-17T05:46:14.991Z",
    "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.

Action not permitted

GHSA-G336-8H5F-6M63

CVE-2026-74354 (GCVE-0-2026-74354)

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Sightings

Nomenclature