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EUVD-2026-320996

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 07:43

Assigner

ENISA

Alias of

a CVE record, shown under related vulnerabilities. This identifier carries no description, severity or references of its own: they belong to that CVE.

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{
  "assigner": "ENISA",
  "date_reserved": "2026-10-02T07:43:29.514847+00:00",
  "id": "EUVD-2026-320996"
}

CVE-2026-43327 (GCVE-0-2026-43327)

Vulnerability from cvelistv5 – Published: 2026-05-08 13:31 – Updated: 2026-05-23 16:06

Title

USB: dummy-hcd: Fix locking/synchronization error

Summary

In the Linux kernel, the following vulnerability has been resolved: USB: dummy-hcd: Fix locking/synchronization error Syzbot testing was able to provoke an addressing exception and crash in the usb_gadget_udc_reset() routine in drivers/usb/gadgets/udc/core.c, resulting from the fact that the routine was called with a second ("driver") argument of NULL. The bad caller was set_link_state() in dummy_hcd.c, and the problem arose because of a race between a USB reset and driver unbind. These sorts of races were not supposed to be possible; commit 7dbd8f4cabd9 ("USB: dummy-hcd: Fix erroneous synchronization change"), along with a few followup commits, was written specifically to prevent them. As it turns out, there are (at least) two errors remaining in the code. Another patch will address the second error; this one is concerned with the first. The error responsible for the syzbot crash occurred because the stop_activity() routine will sometimes drop and then re-acquire the dum->lock spinlock. A call to stop_activity() occurs in set_link_state() when handling an emulated USB reset, after the test of dum->ints_enabled and before the increment of dum->callback_usage. This allowed another thread (doing a driver unbind) to sneak in and grab the spinlock, and then clear dum->ints_enabled and dum->driver. Normally this other thread would have to wait for dum->callback_usage to go down to 0 before it would clear dum->driver, but in this case it didn't have to wait since dum->callback_usage had not yet been incremented. The fix is to increment dum->callback_usage _before_ calling stop_activity() instead of after. Then the thread doing the unbind will not clear dum->driver until after the call to usb_gadget_udc_reset() safely returns and dum->callback_usage has been decremented again.

Severity

No CVSS data available.

Assigner

Linux mitre root Scorecard

References

8 references

URL	Tags
https://git.kernel.org/stable/c/6350c7dd33ab481ef…
https://git.kernel.org/stable/c/cc97fb5969177cccc…
https://git.kernel.org/stable/c/218886b2ef2dea762…
https://git.kernel.org/stable/c/791966f85b439b261…
https://git.kernel.org/stable/c/805b1833d6ed6da50…
https://git.kernel.org/stable/c/efbd9441f1e769a7a…
https://git.kernel.org/stable/c/69ab97a693251d6a6…
https://git.kernel.org/stable/c/616a63ff495df1286…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 , < 6350c7dd33ab481ef41c931a238361490c32d15c (git) Affected: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 , < cc97fb5969177cccce2e23b31298df220fc7570d (git) Affected: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 , < 218886b2ef2dea7627d3700ab0abaf4bf9d1161f (git) Affected: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 , < 791966f85b439b261bf19865cf1c07c065ffb4b4 (git) Affected: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 , < 805b1833d6ed6da5086e610578a28e71bb54fbbb (git) Affected: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 , < efbd9441f1e769a7aae1813d497cec09cbdff031 (git) Affected: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 , < 69ab97a693251d6a6093e630060a3c744fd58524 (git) Affected: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 , < 616a63ff495df12863692ab3f9f7b84e3fa7a66d (git) Affected: 7b416b9dac6ede26d4ca0c1a88b448b543623ff3 (git) Affected: 8590bc1da625dd4a589eac0fc3aa3cf4f400424d (git) Affected: a867d5b932ac4911d3f8a1e63505061b0c81f889 (git) Affected: e84b4a008365b7edbd842a063ae28d040a98db25 (git) Affected: e39b17143a5b5aac81f066d455e5d3a9877eb3ae (git) Affected: 4f8ae1fcb0dfbb72a7678f81bf01fb7fc85c6715 (git) Affected: 3.2.97 , < 3.3 (semver) Affected: 3.16.52 , < 3.17 (semver) Affected: 4.1.46 , < 4.2 (semver) Affected: 4.4.92 , < 4.5 (semver) Affected: 4.9.55 , < 4.10 (semver) Affected: 4.13.6 , < 4.14 (semver)
Linux	Linux	Affected: 4.14 Unaffected: 0 , < 4.14 (semver) Unaffected: 5.10.253 , ≤ 5.10.* (semver) Unaffected: 5.15.203 , ≤ 5.15.* (semver) Unaffected: 6.1.168 , ≤ 6.1.* (semver) Unaffected: 6.6.134 , ≤ 6.6.* (semver) Unaffected: 6.12.81 , ≤ 6.12.* (semver) Unaffected: 6.18.22 , ≤ 6.18.* (semver) Unaffected: 6.19.12 , ≤ 6.19.* (semver) Unaffected: 7.0 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/udc/dummy_hcd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6350c7dd33ab481ef41c931a238361490c32d15c",
              "status": "affected",
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              "versionType": "git"
            },
            {
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              "status": "affected",
              "version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
              "versionType": "git"
            },
            {
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              "status": "affected",
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              "versionType": "git"
            },
            {
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              "versionType": "git"
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            {
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              "versionType": "git"
            },
            {
              "lessThan": "efbd9441f1e769a7aae1813d497cec09cbdff031",
              "status": "affected",
              "version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
              "versionType": "git"
            },
            {
              "lessThan": "69ab97a693251d6a6093e630060a3c744fd58524",
              "status": "affected",
              "version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
              "versionType": "git"
            },
            {
              "lessThan": "616a63ff495df12863692ab3f9f7b84e3fa7a66d",
              "status": "affected",
              "version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "7b416b9dac6ede26d4ca0c1a88b448b543623ff3",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "8590bc1da625dd4a589eac0fc3aa3cf4f400424d",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "a867d5b932ac4911d3f8a1e63505061b0c81f889",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e84b4a008365b7edbd842a063ae28d040a98db25",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "e39b17143a5b5aac81f066d455e5d3a9877eb3ae",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "4f8ae1fcb0dfbb72a7678f81bf01fb7fc85c6715",
              "versionType": "git"
            },
            {
              "lessThan": "3.3",
              "status": "affected",
              "version": "3.2.97",
              "versionType": "semver"
            },
            {
              "lessThan": "3.17",
              "status": "affected",
              "version": "3.16.52",
              "versionType": "semver"
            },
            {
              "lessThan": "4.2",
              "status": "affected",
              "version": "4.1.46",
              "versionType": "semver"
            },
            {
              "lessThan": "4.5",
              "status": "affected",
              "version": "4.4.92",
              "versionType": "semver"
            },
            {
              "lessThan": "4.10",
              "status": "affected",
              "version": "4.9.55",
              "versionType": "semver"
            },
            {
              "lessThan": "4.14",
              "status": "affected",
              "version": "4.13.6",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/usb/gadget/udc/dummy_hcd.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.14"
            },
            {
              "lessThan": "4.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.253",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.203",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.168",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.134",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.81",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.22",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.12",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.253",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.203",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.168",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.134",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.81",
                  "versionStartIncluding": "4.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.22",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.12",
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                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0",
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                  "vulnerable": true
                },
                {
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                  "versionStartIncluding": "3.2.97",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "3.16.52",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.1.46",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "4.4.92",
                  "vulnerable": true
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                {
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                },
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              ],
              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: dummy-hcd: Fix locking/synchronization error\n\nSyzbot testing was able to provoke an addressing exception and crash\nin the usb_gadget_udc_reset() routine in\ndrivers/usb/gadgets/udc/core.c, resulting from the fact that the\nroutine was called with a second (\"driver\") argument of NULL.  The bad\ncaller was set_link_state() in dummy_hcd.c, and the problem arose\nbecause of a race between a USB reset and driver unbind.\n\nThese sorts of races were not supposed to be possible; commit\n7dbd8f4cabd9 (\"USB: dummy-hcd: Fix erroneous synchronization change\"),\nalong with a few followup commits, was written specifically to prevent\nthem.  As it turns out, there are (at least) two errors remaining in\nthe code.  Another patch will address the second error; this one is\nconcerned with the first.\n\nThe error responsible for the syzbot crash occurred because the\nstop_activity() routine will sometimes drop and then re-acquire the\ndum-\u003elock spinlock.  A call to stop_activity() occurs in\nset_link_state() when handling an emulated USB reset, after the test\nof dum-\u003eints_enabled and before the increment of dum-\u003ecallback_usage.\nThis allowed another thread (doing a driver unbind) to sneak in and\ngrab the spinlock, and then clear dum-\u003eints_enabled and dum-\u003edriver.\nNormally this other thread would have to wait for dum-\u003ecallback_usage\nto go down to 0 before it would clear dum-\u003edriver, but in this case it\ndidn\u0027t have to wait since dum-\u003ecallback_usage had not yet been\nincremented.\n\nThe fix is to increment dum-\u003ecallback_usage _before_ calling\nstop_activity() instead of after.  Then the thread doing the unbind\nwill not clear dum-\u003edriver until after the call to\nusb_gadget_udc_reset() safely returns and dum-\u003ecallback_usage has been\ndecremented again."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-23T16:06:42.428Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/6350c7dd33ab481ef41c931a238361490c32d15c"
        },
        {
          "url": "https://git.kernel.org/stable/c/cc97fb5969177cccce2e23b31298df220fc7570d"
        },
        {
          "url": "https://git.kernel.org/stable/c/218886b2ef2dea7627d3700ab0abaf4bf9d1161f"
        },
        {
          "url": "https://git.kernel.org/stable/c/791966f85b439b261bf19865cf1c07c065ffb4b4"
        },
        {
          "url": "https://git.kernel.org/stable/c/805b1833d6ed6da5086e610578a28e71bb54fbbb"
        },
        {
          "url": "https://git.kernel.org/stable/c/efbd9441f1e769a7aae1813d497cec09cbdff031"
        },
        {
          "url": "https://git.kernel.org/stable/c/69ab97a693251d6a6093e630060a3c744fd58524"
        },
        {
          "url": "https://git.kernel.org/stable/c/616a63ff495df12863692ab3f9f7b84e3fa7a66d"
        }
      ],
      "title": "USB: dummy-hcd: Fix locking/synchronization error",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-43327",
    "datePublished": "2026-05-08T13:31:12.896Z",
    "dateReserved": "2026-05-01T14:12:56.002Z",
    "dateUpdated": "2026-05-23T16:06:42.428Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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EUVD-2026-320996

CVE-2026-43327 (GCVE-0-2026-43327)

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