CVE-2026-80920

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: io_uring: defer eventfd signaling when queued from a wakeup handler io_req_local_work_add() signals the CQ ring eventfd inline when it is the one to push the first entry onto ->work_list. For DEFER_TASKRUN rings that add is frequently done from a waitqueue wakeup handler, where an arbitrary waitqueue lock is held. eventfd_signal_mask() only refuses to recurse when current->in_eventfd is set, but that bit is set by eventfd_signal_mask() itself. If the wake chain starts somewhere else, signal goes out inline and can feed back into epoll. Add IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three waitqueue callbacks, and use it to force io_eventfd_signal() down the existing call_rcu_hurry() deferral instead of signaling inline.

Severity

Not scored

CVSS score

Not available

Vulnerability status

Received

Source identifier

416baaa9-dc9f-4396-8d5f-8c081fb06d67

Published

2026-09-09 17:17:47.120000

Last modified

2026-10-21 13:20:01.277000

View original CVE JSON

{
  "id": "CVE-2026-80920",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-09T17:17:47.120",
  "lastModified": "2026-10-21T13:20:01.277",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring: defer eventfd signaling when queued from a wakeup handler\n\nio_req_local_work_add() signals the CQ ring eventfd inline when it is the\none to push the first entry onto ->work_list. For DEFER_TASKRUN rings that\nadd is frequently done from a waitqueue wakeup handler, where an\narbitrary waitqueue lock is held.\n\neventfd_signal_mask() only refuses to recurse when current->in_eventfd\nis set, but that bit is set by eventfd_signal_mask() itself. If the wake\nchain starts somewhere else, signal goes out inline and can feed back\ninto epoll.\n\nAdd IOU_F_TWQ_IN_WAKE, set it on the task_work add done from the three\nwaitqueue callbacks, and use it to force io_eventfd_signal() down the\nexisting call_rcu_hurry() deferral instead of signaling inline."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "include/linux/io_uring_types.h",
            "io_uring/eventfd.c",
            "io_uring/eventfd.h",
            "io_uring/futex.c",
            "io_uring/io_uring.c",
            "io_uring/poll.c",
            "io_uring/tw.c",
            "io_uring/waitid.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "21a091b970cdbcf3e8ff829234b51be6f9192766",
              "lessThan": "d0c240f25e654442a72af5ca021a02165ccce638",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "21a091b970cdbcf3e8ff829234b51be6f9192766",
              "lessThan": "9d984451baf768ecd9e1fdad4637b729fcb2c9d5",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "21a091b970cdbcf3e8ff829234b51be6f9192766",
              "lessThan": "e22f4494cc9487d326e5e3067f33dea7c1e442b2",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "21a091b970cdbcf3e8ff829234b51be6f9192766",
              "lessThan": "b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "21a091b970cdbcf3e8ff829234b51be6f9192766",
              "lessThan": "40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "21a091b970cdbcf3e8ff829234b51be6f9192766",
              "lessThan": "cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "include/linux/io_uring_types.h",
            "io_uring/eventfd.c",
            "io_uring/eventfd.h",
            "io_uring/futex.c",
            "io_uring/io_uring.c",
            "io_uring/poll.c",
            "io_uring/tw.c",
            "io_uring/waitid.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.1",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.1",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.6.160",
              "lessThanOrEqual": "6.6.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.12.114",
              "lessThanOrEqual": "6.12.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.49",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.1.11",
              "lessThanOrEqual": "7.1.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.1",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/40b6ccf68731809ceb85c6e9f0f8f2ed61c7aa5a",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9d984451baf768ecd9e1fdad4637b729fcb2c9d5",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/b6bb334b0e9348887e3e55e1f494b0c3b8fbf59f",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/cd305ee3633a45fcf5f3a5d83f99f3cb77d87b6e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d0c240f25e654442a72af5ca021a02165ccce638",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e22f4494cc9487d326e5e3067f33dea7c1e442b2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}