CVE-2026-43327 (GCVE-0-2026-43327)
Vulnerability from cvelistv5
Published
2026-05-08 13:31
Modified
2026-05-23 16:06
Severity ?
VLAI Severity ?
EPSS score ?
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.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 Version: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 Version: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 Version: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 Version: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 Version: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 Version: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 Version: 7dbd8f4cabd96db5a50513de9d83a8105a5ffc81 Version: 7b416b9dac6ede26d4ca0c1a88b448b543623ff3 Version: 8590bc1da625dd4a589eac0fc3aa3cf4f400424d Version: a867d5b932ac4911d3f8a1e63505061b0c81f889 Version: e84b4a008365b7edbd842a063ae28d040a98db25 Version: e39b17143a5b5aac81f066d455e5d3a9877eb3ae Version: 4f8ae1fcb0dfbb72a7678f81bf01fb7fc85c6715 Version: 3.2.97 ≤ Version: 3.16.52 ≤ Version: 4.1.46 ≤ Version: 4.4.92 ≤ Version: 4.9.55 ≤ Version: 4.13.6 ≤ |
||
{
"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",
"version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
"versionType": "git"
},
{
"lessThan": "cc97fb5969177cccce2e23b31298df220fc7570d",
"status": "affected",
"version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
"versionType": "git"
},
{
"lessThan": "218886b2ef2dea7627d3700ab0abaf4bf9d1161f",
"status": "affected",
"version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
"versionType": "git"
},
{
"lessThan": "791966f85b439b261bf19865cf1c07c065ffb4b4",
"status": "affected",
"version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
"versionType": "git"
},
{
"lessThan": "805b1833d6ed6da5086e610578a28e71bb54fbbb",
"status": "affected",
"version": "7dbd8f4cabd96db5a50513de9d83a8105a5ffc81",
"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",
"versionStartIncluding": "4.14",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.19.12",
"versionStartIncluding": "4.14",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.0",
"versionStartIncluding": "4.14",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"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
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "4.9.55",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "4.13.6",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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"
}
Loading…
Loading…
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
Loading…
Loading…