{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-31726", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-03-09T15:48:24.134Z", "datePublished": "2026-05-01T14:14:26.882Z", "dateUpdated": "2026-05-23T16:05:51.035Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-23T16:05:51.035Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: uvc: fix NULL pointer dereference during unbind race\n\nCommit b81ac4395bbe (\"usb: gadget: uvc: allow for application to cleanly\nshutdown\") introduced two stages of synchronization waits totaling 1500ms\nin uvc_function_unbind() to prevent several types of kernel panics.\nHowever, this timing-based approach is insufficient during power\nmanagement (PM) transitions.\n\nWhen the PM subsystem starts freezing user space processes, the\nwait_event_interruptible_timeout() is aborted early, which allows the\nunbind thread to proceed and nullify the gadget pointer\n(cdev->gadget = NULL):\n\n[ 814.123447][ T947] configfs-gadget.g1 gadget.0: uvc: uvc_function_unbind()\n[ 814.178583][ T3173] PM: suspend entry (deep)\n[ 814.192487][ T3173] Freezing user space processes\n[ 814.197668][ T947] configfs-gadget.g1 gadget.0: uvc: uvc_function_unbind no clean disconnect, wait for release\n\nWhen the PM subsystem resumes or aborts the suspend and tasks are\nrestarted, the V4L2 release path is executed and attempts to access the\nalready nullified gadget pointer, triggering a kernel panic:\n\n[ 814.292597][ C0] PM: pm_system_irq_wakeup: 479 triggered dhdpcie_host_wake\n[ 814.386727][ T3173] Restarting tasks ...\n[ 814.403522][ T4558] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000030\n[ 814.404021][ T4558] pc : usb_gadget_deactivate+0x14/0xf4\n[ 814.404031][ T4558] lr : usb_function_deactivate+0x54/0x94\n[ 814.404078][ T4558] Call trace:\n[ 814.404080][ T4558] usb_gadget_deactivate+0x14/0xf4\n[ 814.404083][ T4558] usb_function_deactivate+0x54/0x94\n[ 814.404087][ T4558] uvc_function_disconnect+0x1c/0x5c\n[ 814.404092][ T4558] uvc_v4l2_release+0x44/0xac\n[ 814.404095][ T4558] v4l2_release+0xcc/0x130\n\nAddress the race condition and NULL pointer dereference by:\n\n1. State Synchronization (flag + mutex)\nIntroduce a 'func_unbound' flag in struct uvc_device. This allows\nuvc_function_disconnect() to safely skip accessing the nullified\ncdev->gadget pointer. As suggested by Alan Stern, this flag is protected\nby a new mutex (uvc->lock) to ensure proper memory ordering and prevent\ninstruction reordering or speculative loads. This mutex is also used to\nprotect 'func_connected' for consistent state management.\n\n2. Explicit Synchronization (completion)\nUse a completion to synchronize uvc_function_unbind() with the\nuvc_vdev_release() callback. This prevents Use-After-Free (UAF) by\nensuring struct uvc_device is freed after all video device resources\nare released." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/function/f_uvc.c", "drivers/usb/gadget/function/uvc.h", "drivers/usb/gadget/function/uvc_v4l2.c" ], "versions": [ { "version": "1444e0568bc2c70868e7b8da5b46fc2252acc3f5", "lessThan": "0c00ec409d7b2bce3fcac73188b79a141db7cfda", "status": "affected", "versionType": "git" }, { "version": "4962e5a2f301d24953f17d6748d986e21566abe1", "lessThan": "d92d1532e05b1b31d36d48765e43bf73d793d19f", "status": "affected", "versionType": "git" }, { "version": "b81ac4395bbeaf36e078dea1a48c02dd97b76235", "lessThan": "0587de744615628c38e33ddc1601160a5ea8c50a", "status": "affected", "versionType": "git" }, { "version": "b81ac4395bbeaf36e078dea1a48c02dd97b76235", "lessThan": "c78e463ee134b4669579d453c81ae00795e4c19a", "status": "affected", "versionType": "git" }, { "version": "b81ac4395bbeaf36e078dea1a48c02dd97b76235", "lessThan": "8a1128d604c360eca135f15b882b70256a522145", "status": "affected", "versionType": "git" }, { "version": "b81ac4395bbeaf36e078dea1a48c02dd97b76235", "lessThan": "1aa9356881ee4ed414bf72d0c56d915492cb5345", "status": "affected", "versionType": "git" }, { "version": "b81ac4395bbeaf36e078dea1a48c02dd97b76235", "lessThan": "c038ba56b92e410d1caec22b2dc68780a0b42091", "status": "affected", "versionType": "git" }, { "version": "b81ac4395bbeaf36e078dea1a48c02dd97b76235", "lessThan": "eba2936bbe6b752a31725a9eb5c674ecbf21ee7d", "status": "affected", "versionType": "git" }, { "version": "e10735ce87502b07e171727e574afdd6c0890a08", "status": "affected", "versionType": "git" }, { "version": "5.10.117", "lessThan": "5.10.253", "status": "affected", "versionType": "semver" }, { "version": "5.15.41", "lessThan": "5.15.203", "status": "affected", "versionType": "semver" }, { "version": "5.17.9", "lessThan": "5.18", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/usb/gadget/function/f_uvc.c", "drivers/usb/gadget/function/uvc.h", "drivers/usb/gadget/function/uvc_v4l2.c" ], "versions": [ { "version": "5.18", "status": "affected" }, { "version": "0", "lessThan": "5.18", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.253", "lessThanOrEqual": "5.10.*", "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": "5.10.117", "versionEndExcluding": "5.10.253" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.41", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.1.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.6.134" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.12.81" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.18.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "6.19.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.18", "versionEndExcluding": "7.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/0c00ec409d7b2bce3fcac73188b79a141db7cfda" }, { "url": "https://git.kernel.org/stable/c/d92d1532e05b1b31d36d48765e43bf73d793d19f" }, { "url": "https://git.kernel.org/stable/c/0587de744615628c38e33ddc1601160a5ea8c50a" }, { "url": "https://git.kernel.org/stable/c/c78e463ee134b4669579d453c81ae00795e4c19a" }, { "url": "https://git.kernel.org/stable/c/8a1128d604c360eca135f15b882b70256a522145" }, { "url": "https://git.kernel.org/stable/c/1aa9356881ee4ed414bf72d0c56d915492cb5345" }, { "url": "https://git.kernel.org/stable/c/c038ba56b92e410d1caec22b2dc68780a0b42091" }, { "url": "https://git.kernel.org/stable/c/eba2936bbe6b752a31725a9eb5c674ecbf21ee7d" } ], "title": "usb: gadget: uvc: fix NULL pointer dereference during unbind race", "x_generator": { "engine": "bippy-1.2.0" } } } }