CVE-2026-74646 (GCVE-0-2026-74646)

Vulnerability from cvelistv5 – Published: 2026-08-22 15:32 – Updated: 2026-08-25 05:41
VLAI
Title
misc: fastrpc: take fl->lock when moving mmaps on interrupted invoke
Summary
In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: take fl->lock when moving mmaps on interrupted invoke When an invoke is interrupted by a signal, wait_for_completion_interruptible() returns -ERESTARTSYS and fastrpc_internal_invoke() moves every buffer from fl->mmaps onto cctx->invoke_interrupted_mmaps. This list_del()/list_add_tail() walk runs without holding fl->lock, the lock that serialises fl->mmaps in fastrpc_req_mmap() and fastrpc_req_munmap() everywhere else. Take fl->lock around the move, matching every other fl->mmaps accessor.
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: 76e8e4ace1ed2c97dba3b1370e0e105e07c572bc , < 3f265e405e5ef85030c3777262e18bb556bc8724 (git)
Affected: 76e8e4ace1ed2c97dba3b1370e0e105e07c572bc , < a902fe1f80f58a2335b6be1131866f827ec44d1a (git)
Affected: 76e8e4ace1ed2c97dba3b1370e0e105e07c572bc , < af6345159abcbaa550518f31990d2a9558c2d369 (git)
Affected: 76e8e4ace1ed2c97dba3b1370e0e105e07c572bc , < efd02f8d1a7449f15809bc18d3cd41aafea75d7e (git)
Affected: 76e8e4ace1ed2c97dba3b1370e0e105e07c572bc , < b85a0e91d7d6cd06a53c881a46f749cfcef416a2 (git)
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Linux Linux Affected: 6.2
Unaffected: 0 , < 6.2 (semver)
Unaffected: 6.6.152 , ≤ 6.6.* (semver)
Unaffected: 6.12.104 , ≤ 6.12.* (semver)
Unaffected: 6.18.45 , ≤ 6.18.* (semver)
Unaffected: 7.1.9 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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            "version": "3.1"
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              "value": "AV:L - Reachable only through local ioctl on the Qualcomm FastRPC miscdevice (/dev/fastrpc-*); communication with the DSP is internal rpmsg/glink IPC on the SoC, not via network or adjacent wireless protocols.\nAC:L - Attacker controls both sides: one thread blocks in FASTRPC_IOCTL_INVOKE, delivers a signal to force -ERESTARTSYS, and another thread issues concurrent FASTRPC_IOCTL_MMAP/MUNMAP on the same fd; the race can be retried until it wins.\nPR:L - fastrpc_device_ioctl has no capability check; on Qualcomm/Android deployments non-root processes with FastRPC device access (HALs, system services, or unsigned-PD offload clients) can open the node and hit the vulnerable path without real root.\nUI:N - No victim interaction is required beyond the attacker\u0027s own local access; exploitation uses attacker-controlled threads and signals to race ioctls on an already-open FastRPC file descriptor.\nS:U - The bug corrupts kernel linked-list/heap state in the host OS FastRPC driver; impact is local kernel privilege escalation within the same security authority, not a VM escape or IOMMU boundary bypass.\nC:H - Unsynchronized list_del/list_add_tail on fl-\u003emmaps corrupts kernel list pointers and can orphan or double-reference fastrpc_buf objects, enabling use-after-free and kernel memory disclosure primitives.\nI:H - Corrupting mmap tracking list nodes in kernel heap can yield double-free or use-after-free of fastrpc_buf slabs, which are standard primitives for arbitrary kernel write and control-flow hijacking.\nA:H - List corruption on fl-\u003emmaps reliably causes kernel oops/panic during subsequent mmap/munmap or user teardown; repeated ioctl racing can crash or hang the device."
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          "url": "https://git.kernel.org/stable/c/b85a0e91d7d6cd06a53c881a46f749cfcef416a2"
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    "datePublished": "2026-08-22T15:32:23.378Z",
    "dateReserved": "2026-08-15T05:44:03.923Z",
    "dateUpdated": "2026-08-25T05:41:04.331Z",
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      "title": "misc: fastrpc: take fl-\u003elock when moving mmaps on interrupted invoke",
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-25T08:52:45+00:00",
      "cve": "CVE-2026-74646",
      "id": "CVE-2026-74646",
      "initial_release_date": "2026-08-22T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: misc: fastrpc: take fl-\u003elock when moving mmaps on interrupted invoke",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-74646.json",
      "version": "3"
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}



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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.

Sightings

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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.
  • 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.