CVE-2026-89738

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89738", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.761Z", "datePublished": "2026-09-11T19:46:45.898Z", "dateUpdated": "2026-10-30T12:32:52.839Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:32:52.839Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed\n\nIn polled-VBUS mode (board.vbus_pin && board.vbus_polled), probe arms a\nself-restarting cycle: at91_vbus_timer() schedules vbus_timer_work, and\nat91_vbus_timer_work() calls at91_vbus_update() and re-arms the timer via\nmod_timer(). Both recover the same udc through container_of and dereference\nit on every iteration.\n\nNeither teardown path cancels this cycle. udc is devm-allocated, so it is\nfreed after at91udc_remove() returns, and is likewise freed when probe\nfails and devres runs. A timer callback or work item that is pending or\nrunning at either point dereferences the freed udc.\n\nAdd at91_udc_shutdown_vbus_timer() and call it from at91udc_remove() and\nfrom the usb_add_gadget_udc() failure path in probe; the remaining probe\nerror paths fail before the timer is armed. timer_shutdown_sync() waits\nfor a running callback and clears timer->function, which makes the work\nhandler's mod_timer() a permanent no-op; cancel_work_sync() then drains\nany pending or running work whose re-arm attempt now does nothing. The\ntimer must be shut down first, since cancelling the work alone would let\nthe timer re-queue it. The guard mirrors probe: in IRQ mode the timer and\nwork_struct are never initialized.\n\nThis does not require a fault; a normal driver unbind can interleave with\nan already queued work item.\n\nThis issue was found by an in-house static analysis tool."}], "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 use-after-free is reached on local AT91 UDC platform-driver teardown (sysfs unbind, rmmod, or probe-error unwind after the polled-VBUS timer is armed), not by parsing USB host packets. That matches other USB gadget/UDC teardown UAFs scored Local and is higher severity than Physical.\nAC:L - Once polled-VBUS mode is active, unbind or the usb_add_gadget_udc() failure path frees the devm-allocated udc while the self-restarting timer/work still hold it; the next timer tick or already-queued work then dereferences the freed object with no race the attacker cannot drive.\nPR:L - Highest reasonable exposure is a local account that manages the USB gadget/UDC on AT91 industrial, IoT, and embedded controllers, where platform unbind or gadget HAL access is often delegated beyond init-namespace root. Uncertain Low vs High, so Low per the overestimate rule.\nUI:N - The attacker initiates driver unbind, module unload, or a failing re-probe themselves; no separate victim action such as plugging a USB cable, mounting a filesystem, or opening a device node is required.\nS:U - The use-after-free corrupts the host kernel's struct at91_udc heap object within the same OS security authority and does not cross a VM, IOMMU, or sandbox boundary.\nC:H - at91_vbus_timer() and at91_vbus_timer_work() recover the freed udc via container_of and read vbus_pin, gadget state, and related fields; reclaiming that slab yields a classic UAF read/disclosure primitive.\nI:H - The dangling work calls at91_vbus_session()/pullup(), which write MMIO through udp_baseaddr and invoke caps->pullup and possibly driver->disconnect on the freed object, enabling heap corruption and control-flow hijack.\nA:H - Dereferencing the freed udc from timer or workqueue context causes a kernel oops or panic even without a full exploit, so availability impact is High."}]}], "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/at91_udc.c"], "versions": [{"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "lessThan": "2440ce54b8c4c8aa6963c181eb56164a466fbe1c", "status": "affected", "versionType": "git"}, {"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "lessThan": "1674e34fe61ad3f5585dc833ba6bb6522912e6a5", "status": "affected", "versionType": "git"}, {"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "lessThan": "723d73b245843d4fff4c3f42e857c78c2b2d414e", "status": "affected", "versionType": "git"}, {"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "lessThan": "a2a602cb1e28d76a5398cec3fa21b0110385f501", "status": "affected", "versionType": "git"}, {"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "lessThan": "51a311eb97e91ce1aed3005cb71ccb2e30f8cce8", "status": "affected", "versionType": "git"}, {"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "lessThan": "557ef547d49ff5e6026a4d39bdd3113bd81d7688", "status": "affected", "versionType": "git"}, {"version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "lessThan": "c27d13ce4bab80fbdf6523928071b6c24b37606c", "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/at91_udc.c"], "versions": [{"version": "2.6.36", "status": "affected"}, {"version": "0", "lessThan": "2.6.36", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.224", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "2.6.36", "versionEndExcluding": "5.15.224"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.36", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/2440ce54b8c4c8aa6963c181eb56164a466fbe1c"}, {"url": "https://git.kernel.org/stable/c/1674e34fe61ad3f5585dc833ba6bb6522912e6a5"}, {"url": "https://git.kernel.org/stable/c/723d73b245843d4fff4c3f42e857c78c2b2d414e"}, {"url": "https://git.kernel.org/stable/c/a2a602cb1e28d76a5398cec3fa21b0110385f501"}, {"url": "https://git.kernel.org/stable/c/51a311eb97e91ce1aed3005cb71ccb2e30f8cce8"}, {"url": "https://git.kernel.org/stable/c/557ef547d49ff5e6026a4d39bdd3113bd81d7688"}, {"url": "https://git.kernel.org/stable/c/c27d13ce4bab80fbdf6523928071b6c24b37606c"}], "title": "usb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/usb/gadget/udc/at91_udc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "2440ce54b8c4c8aa6963c181eb56164a466fbe1c", "status": "affected", "version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "versionType": "git"}, {"lessThan": "1674e34fe61ad3f5585dc833ba6bb6522912e6a5", "status": "affected", "version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "versionType": "git"}, {"lessThan": "723d73b245843d4fff4c3f42e857c78c2b2d414e", "status": "affected", "version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "versionType": "git"}, {"lessThan": "a2a602cb1e28d76a5398cec3fa21b0110385f501", "status": "affected", "version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "versionType": "git"}, {"lessThan": "51a311eb97e91ce1aed3005cb71ccb2e30f8cce8", "status": "affected", "version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "versionType": "git"}, {"lessThan": "557ef547d49ff5e6026a4d39bdd3113bd81d7688", "status": "affected", "version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "versionType": "git"}, {"lessThan": "c27d13ce4bab80fbdf6523928071b6c24b37606c", "status": "affected", "version": "4037242c4f5ff77afe61bf07ca1e8a99490219e5", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/usb/gadget/udc/at91_udc.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "2.6.36"}, {"lessThan": "2.6.36", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.224", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.160", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.109", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: at91_udc: drain polled-VBUS timer/work before udc is freed\n\nIn polled-VBUS mode (board.vbus_pin && board.vbus_polled), probe arms a\nself-restarting cycle: at91_vbus_timer() schedules vbus_timer_work, and\nat91_vbus_timer_work() calls at91_vbus_update() and re-arms the timer via\nmod_timer(). Both recover the same udc through container_of and dereference\nit on every iteration.\n\nNeither teardown path cancels this cycle. udc is devm-allocated, so it is\nfreed after at91udc_remove() returns, and is likewise freed when probe\nfails and devres runs. A timer callback or work item that is pending or\nrunning at either point dereferences the freed udc.\n\nAdd at91_udc_shutdown_vbus_timer() and call it from at91udc_remove() and\nfrom the usb_add_gadget_udc() failure path in probe; the remaining probe\nerror paths fail before the timer is armed. timer_shutdown_sync() waits\nfor a running callback and clears timer->function, which makes the work\nhandler's mod_timer() a permanent no-op; cancel_work_sync() then drains\nany pending or running work whose re-arm attempt now does nothing. The\ntimer must be shut down first, since cancelling the work alone would let\nthe timer re-queue it. The guard mirrors probe: in IRQ mode the timer and\nwork_struct are never initialized.\n\nThis does not require a fault; a normal driver unbind can interleave with\nan already queued work item.\n\nThis issue was found by an in-house static analysis tool."}], "id": "CVE-2026-89738", "lastModified": "2026-10-30T13:20:27.713", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-11T20:20:04.357", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/1674e34fe61ad3f5585dc833ba6bb6522912e6a5"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2440ce54b8c4c8aa6963c181eb56164a466fbe1c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/51a311eb97e91ce1aed3005cb71ccb2e30f8cce8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/557ef547d49ff5e6026a4d39bdd3113bd81d7688"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/723d73b245843d4fff4c3f42e857c78c2b2d414e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a2a602cb1e28d76a5398cec3fa21b0110385f501"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c27d13ce4bab80fbdf6523928071b6c24b37606c"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: USB gadget `at91_udc` driver use-after-free vulnerability", "id": "2532232", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532232"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.1", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["A flaw was found in the Linux kernel's `at91_udc` USB gadget driver. In polled-VBUS mode, a timing issue during driver unbinding or probe failure can lead to a use-after-free vulnerability. A local attacker could exploit this by triggering a normal driver unbind operation, which may interleave with an already queued work item. This could result in system instability or a denial of service (DoS) due to the driver attempting to access freed memory."], "name": "CVE-2026-89738", "public_date": "2026-09-11T19:46:45Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89738\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89738\nhttps://git.kernel.org/stable/c/51a311eb97e91ce1aed3005cb71ccb2e30f8cce8\nhttps://git.kernel.org/stable/c/557ef547d49ff5e6026a4d39bdd3113bd81d7688\nhttps://git.kernel.org/stable/c/a2a602cb1e28d76a5398cec3fa21b0110385f501\nhttps://git.kernel.org/stable/c/c27d13ce4bab80fbdf6523928071b6c24b37606c"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4037242c4f5ff77afe61bf07ca1e8a99490219e5,a2a602cb1e28d76a5398cec3fa21b0110385f501)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4037242c4f5ff77afe61bf07ca1e8a99490219e5,51a311eb97e91ce1aed3005cb71ccb2e30f8cce8)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4037242c4f5ff77afe61bf07ca1e8a99490219e5,557ef547d49ff5e6026a4d39bdd3113bd81d7688)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[4037242c4f5ff77afe61bf07ca1e8a99490219e5,c27d13ce4bab80fbdf6523928071b6c24b37606c)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "2.6.36"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,2.6.36)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.109,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.50,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.4,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-12T05:15:06.926596+00:00", "updated": "2026-09-15T21:30:16.420541+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}