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

Vulnerability from cvelistv5 – Published: 2026-08-15 05:58 – Updated: 2026-08-17 05:46
VLAI
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
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 317460317a02a1af512697e6e964298dedd8a163 , < 36b1d997866f6083d33934983aa2ce0a184ed642 (git)
Affected: 317460317a02a1af512697e6e964298dedd8a163 , < 80b89d0226a05e8b67969de99c31b51fcd54f76a (git)
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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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        }
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            "baseSeverity": "HIGH",
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              "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."
            }
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      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:46:14.991Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/36b1d997866f6083d33934983aa2ce0a184ed642"
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        {
          "url": "https://git.kernel.org/stable/c/80b89d0226a05e8b67969de99c31b51fcd54f76a"
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      "title": "bpf: Take mmap_lock in zap_pages()",
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    "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"
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-19T10:01:33+00:00",
      "cve": "CVE-2026-74354",
      "id": "CVE-2026-74354",
      "initial_release_date": "2026-08-15T00:00:00+00:00",
      "product_status:known_affected": "184",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bpf: Take mmap_lock in zap_pages()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74354.json",
      "version": "3"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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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.
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  • 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.


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