# CVE-2026-64425: io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item

Status: published. Published: 2026-07-25. Updated: 2026-11-10.

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

io_uring/io-wq: re-check IO_WQ_BIT_EXIT for each linked work item

commit 10dc95939817 ("io_uring/io-wq: check IO_WQ_BIT_EXIT inside work
run loop") fixed the obvious case where io_worker_handle_work() took one
exit-bit snapshot before draining pending work, but the fix stops one
level too early.

io_worker_handle_work() now re-checks IO_WQ_BIT_EXIT in its outer work
run loop, yet it still snapshots that bit once before processing a whole
dependent linked-work chain. If io_wq_exit_start() sets IO_WQ_BIT_EXIT
after the first linked item has started, the remaining linked items can
still reuse stale do_kill = false, skip IO_WQ_WORK_CANCEL, and continue
running after exit has begun.

Move the check further inside, so it covers linked items too. Note: this
is a syzbot special as it loves setting up tons of slow linked work on
weird devices like msr that take forever to read, and immediately close
the ring. Exit then takes a long time.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/14b7ecad2ec56699325180a744f4b19f046401bb
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/1636d85dc139b07c0449308f2bb5e0c7a2e0da99
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/29bef9934b2521f787bb15dd1985d4c0d12ae02a
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/6e2f51f3e06773c2ee98ad09738f0908b48f76f9
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/ab85765cbe3258b43dc6729af0e6ce3a87a133d8
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/b6f179a653a934736c88d820fe0098c3c2532549
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/d179533c610e1b4c6aa436e3c1fd1b719d2c727c
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67) — https://git.kernel.org/stable/c/ea61b04e1d7242cb37f5ed2cc91cf21a493f6597

## Affected products and versions

- Linux / Linux: ≥ 065dd936195a3466b8ebe5f9287400987ee3c063; < 14b7ecad2ec56699325180a744f4b19f046401bb (affected, git); ≥ 27e47500fac23d15b7dc93ff650bc4844d2581bd; < d179533c610e1b4c6aa436e3c1fd1b719d2c727c (affected, git); ≥ d05d99573f81a091547b1778b9a50120f5d6c68a; < 6e2f51f3e06773c2ee98ad09738f0908b48f76f9 (affected, git); ≥ 85eb83694a91c89d9abe615d717c0053c3efa714; < ea61b04e1d7242cb37f5ed2cc91cf21a493f6597 (affected, git); ≥ 2e8ca1078b14142db2ce51cbd18ff9971560046b; < b6f179a653a934736c88d820fe0098c3c2532549 (affected, git); ≥ bdf0bf73006ea8af9327cdb85cfdff4c23a5f966; < 1636d85dc139b07c0449308f2bb5e0c7a2e0da99 (affected, git); ≥ 10dc959398175736e495f71c771f8641e1ca1907; < ab85765cbe3258b43dc6729af0e6ce3a87a133d8 (affected, git); ≥ 10dc959398175736e495f71c771f8641e1ca1907; < 29bef9934b2521f787bb15dd1985d4c0d12ae02a (affected, git); ≥ 5.10.253; < 5.10.261 (affected, semver); ≥ 5.15.203; < 5.15.212 (affected, semver); ≥ 6.1.167; < 6.1.178 (affected, semver); ≥ 6.6.122; < 6.6.145 (affected, semver); ≥ 6.12.68; < 6.12.96 (affected, semver); ≥ 6.18.8; < 6.18.39 (affected, semver). Source: CNA: Linux
- Linux / Linux: 6.19 (affected); ≥ 0; < 6.19 (unaffected, semver); ≥ 5.10.261; ≤ 5.10.* (unaffected, semver); ≥ 5.15.212; ≤ 5.15.* (unaffected, semver); ≥ 6.1.178; ≤ 6.1.* (unaffected, semver); ≥ 6.6.145; ≤ 6.6.* (unaffected, semver); ≥ 6.12.96; ≤ 6.12.* (unaffected, semver); ≥ 6.18.39; ≤ 6.18.* (unaffected, semver); ≥ 7.1.4; ≤ 7.1.* (unaffected, semver); ≥ 7.2; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.6; < * (affected, custom). Source: ADP: siemens-SADP
- Siemens / SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0): ≥ V3.1.7; < * (affected, custom). Source: ADP: siemens-SADP

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "5.10.261",
            "versionStartIncluding": "5.10.253",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "5.15.212",
            "versionStartIncluding": "5.15.203",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.1.178",
            "versionStartIncluding": "6.1.167",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.6.145",
            "versionStartIncluding": "6.6.122",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.12.96",
            "versionStartIncluding": "6.12.68",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "6.18.39",
            "versionStartIncluding": "6.18.8",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "7.1.4",
            "versionStartIncluding": "6.19.1",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:*",
            "vulnerable": true
          },
          {
            "criteria": "cpe:2.3:o:linux:linux_kernel:6.19:rc8:*:*:*:*:*:*",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 5.5 (medium); CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: NVD: nvd@nist.gov

- CISA KEV: No listing in collected sources

- EPSS: 0.13% as of 2026-11-09; percentile 2.54%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/14b7ecad2ec56699325180a744f4b19f046401bb (CNA: Linux)

- https://git.kernel.org/stable/c/d179533c610e1b4c6aa436e3c1fd1b719d2c727c (CNA: Linux)

- https://git.kernel.org/stable/c/6e2f51f3e06773c2ee98ad09738f0908b48f76f9 (CNA: Linux)

- https://git.kernel.org/stable/c/ea61b04e1d7242cb37f5ed2cc91cf21a493f6597 (CNA: Linux)

- https://git.kernel.org/stable/c/b6f179a653a934736c88d820fe0098c3c2532549 (CNA: Linux)

- https://git.kernel.org/stable/c/1636d85dc139b07c0449308f2bb5e0c7a2e0da99 (CNA: Linux)

- https://git.kernel.org/stable/c/ab85765cbe3258b43dc6729af0e6ce3a87a133d8 (CNA: Linux)

- https://git.kernel.org/stable/c/29bef9934b2521f787bb15dd1985d4c0d12ae02a (CNA: Linux)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (ADP: siemens-SADP)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (ADP: siemens-SADP)

- https://git.kernel.org/stable/c/14b7ecad2ec56699325180a744f4b19f046401bb (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/1636d85dc139b07c0449308f2bb5e0c7a2e0da99 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/29bef9934b2521f787bb15dd1985d4c0d12ae02a (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/6e2f51f3e06773c2ee98ad09738f0908b48f76f9 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/ab85765cbe3258b43dc6729af0e6ce3a87a133d8 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/b6f179a653a934736c88d820fe0098c3c2532549 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/d179533c610e1b4c6aa436e3c1fd1b719d2c727c (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://git.kernel.org/stable/c/ea61b04e1d7242cb37f5ed2cc91cf21a493f6597 (416baaa9-dc9f-4396-8d5f-8c081fb06d67; Patch)

- https://cert-portal.siemens.com/productcert/html/ssa-019113.html (0b142b55-0307-4c5a-b3c9-f314f3fb7c5e)

- https://cert-portal.siemens.com/productcert/html/ssa-457936.html (0b142b55-0307-4c5a-b3c9-f314f3fb7c5e)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-64425; retrieved 2026-11-10; source updated 2026-11-10

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64425; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-64425; retrieved 2026-11-10; source updated Not reported

Revision: e96a32c21e3939d2c4b58ad0c8165132b5441a5e40375ef1714431f9e838597a

Canonical: https://y2.dev/cve/CVE-2026-64425

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