{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43324", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.002Z", "datePublished": "2026-05-08T13:31:08.850Z", "dateUpdated": "2026-08-05T12:27:14.134Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:27:14.134Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nUSB: dummy-hcd: Fix interrupt synchronization error\n\nThis fixes an error in synchronization in the dummy-hcd driver. The\nerror has a somewhat involved history. The synchronization mechanism\nwas introduced by commit 7dbd8f4cabd9 (\"USB: dummy-hcd: Fix erroneous\nsynchronization change\"), which added an emulated \"interrupts enabled\"\nflag together with code emulating synchronize_irq() (it waits until\nall current handler callbacks have returned).\n\nBut the emulated interrupt-disable occurred too late, after the driver\ncontaining the handler callback routines had been told that it was\nunbound and no more callbacks would occur. Commit 4a5d797a9f9c (\"usb:\ngadget: dummy_hcd: fix gpf in gadget_setup\") tried to fix this by\nmoving the synchronize_irq() emulation code from dummy_stop() to\ndummy_pullup(), which runs before the unbind callback.\n\nThere still were races, though, because the emulated interrupt-disable\nstill occurred too late. It couldn't be moved to dummy_pullup(),\nbecause that routine can be called for reasons other than an impending\nunbind. Therefore commits 7dc0c55e9f30 (\"USB: UDC core: Add\nudc_async_callbacks gadget op\") and 04145a03db9d (\"USB: UDC: Implement\nudc_async_callbacks in dummy-hcd\") added an API allowing the UDC core\nto tell dummy-hcd exactly when emulated interrupts and their callbacks\nshould be disabled.\n\nThat brings us to the current state of things, which is still wrong\nbecause the emulated synchronize_irq() occurs before the emulated\ninterrupt-disable! That's no good, beause it means that more emulated\ninterrupts can occur after the synchronize_irq() emulation has run,\nleading to the possibility that a callback handler may be running when\nthe gadget driver is unbound.\n\nTo fix this, we have to move the synchronize_irq() emulation code yet\nagain, to the dummy_udc_async_callbacks() routine, which takes care of\nenabling and disabling emulated interrupt requests. The\nsynchronization will now run immediately after emulated interrupts are\ndisabled, which is where it belongs." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerable dummy-hcd path is reached through local USB gadget/host emulator interfaces such as raw-gadget, usbfs, configfs, or sysfs unbind paths. It is not network-reachable and dummy-hcd is an in-kernel emulator rather than a physically attached USB device.\nAC:L - Although this is a race, a local attacker can drive both sides by generating emulated USB activity while triggering gadget driver unbind, and the race can be retried. There are no special external conditions beyond attacker-controlled timing.\nPR:L - Exploitation requires local access to the configured dummy-hcd/gadget userspace interfaces, but the relevant raw-gadget and usbfs paths do not themselves impose a kernel capability check once accessible. When uncertain between root-only setup and normal local device access, the higher-severity PR:L is appropriate.\nUI:N - No victim action is needed after the attacker has local access to the relevant device interfaces. The attacker can trigger emulated USB callbacks and unbind locally.\nS:U - The impact remains within the same kernel security authority. This is a standard local kernel memory-safety/availability issue, not a VM escape or cross-authority boundary violation.\nC:H - The synchronization bug can allow asynchronous gadget callbacks to run after or during gadget driver unbind, leaving callback code operating on stale or cleared gadget-driver state. This is a use-after-unbind/use-after-free class condition, so kernel memory disclosure is a defensible worst-case impact.\nI:H - Callback execution against freed or invalid gadget-driver state can be leveraged as kernel memory corruption rather than merely a clean failure. Under the required higher-severity rule, a UAF-style kernel race supports potential arbitrary write or code execution.\nA:H - At minimum, the race can crash the kernel through NULL dereference or stale pointer use in gadget callbacks, as related dummy-hcd synchronization bugs have done. Kernel oops/panic is high availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/udc/dummy_hcd.c" ], "versions": [ { "version": "04145a03db9d78469e0817ab3a767c76c0fb0947", "lessThan": "d847f375b1bcea713143bc02720d13d2d01b012a", "status": "affected", "versionType": "git" }, { "version": "04145a03db9d78469e0817ab3a767c76c0fb0947", "lessThan": "cbf7df5e5d27cd5bea92ee9a75a4b28dbcc718d4", "status": "affected", "versionType": "git" }, { "version": "04145a03db9d78469e0817ab3a767c76c0fb0947", "lessThan": "5aa776c8615bea3b1eaeec87b0788375800ead4f", "status": "affected", "versionType": "git" }, { "version": "04145a03db9d78469e0817ab3a767c76c0fb0947", "lessThan": "94d4fab1dd9e64f45449bcc7d6a5acf796b13015", "status": "affected", "versionType": "git" }, { "version": "04145a03db9d78469e0817ab3a767c76c0fb0947", "lessThan": "5687a09776069bd915560021c9728ca528440128", "status": "affected", "versionType": "git" }, { "version": "04145a03db9d78469e0817ab3a767c76c0fb0947", "lessThan": "8bcd80219d8e10e660bf29b20e41bb8beb4e4cb7", "status": "affected", "versionType": "git" }, { "version": "04145a03db9d78469e0817ab3a767c76c0fb0947", "lessThan": "2ca9e46f8f1f5a297eb0ac83f79d35d5b3a02541", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/udc/dummy_hcd.c" ], "versions": [ { "version": "5.14", "status": "affected" }, { "version": "0", "lessThan": "5.14", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.203", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.168", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.134", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.81", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.22", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.12", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.1.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.6.134" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.12.81" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.18.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "6.19.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d847f375b1bcea713143bc02720d13d2d01b012a" }, { "url": "https://git.kernel.org/stable/c/cbf7df5e5d27cd5bea92ee9a75a4b28dbcc718d4" }, { "url": "https://git.kernel.org/stable/c/5aa776c8615bea3b1eaeec87b0788375800ead4f" }, { "url": "https://git.kernel.org/stable/c/94d4fab1dd9e64f45449bcc7d6a5acf796b13015" }, { "url": "https://git.kernel.org/stable/c/5687a09776069bd915560021c9728ca528440128" }, { "url": "https://git.kernel.org/stable/c/8bcd80219d8e10e660bf29b20e41bb8beb4e4cb7" }, { "url": "https://git.kernel.org/stable/c/2ca9e46f8f1f5a297eb0ac83f79d35d5b3a02541" } ], "title": "USB: dummy-hcd: Fix interrupt synchronization error", "x_generator": { "engine": "bippy-1.2.0" } } } }