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io_uring: defer eventfd signaling when queued from a wakeup handler

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

CVE-2026-80920

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-80920

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "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"
      }
    ],
    "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"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "6.1"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "6.1",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.114",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.49",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.11",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.1",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "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"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-80920

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#46646 · Revision 1
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Publisher date
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