{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-49755", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-03-27T16:39:17.988Z", "datePublished": "2025-03-27T16:43:02.950Z", "dateUpdated": "2026-08-05T08:56:13.355Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:56:13.355Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait\n\nWhile performing fast composition switch, there is a possibility that the\nprocess of ffs_ep0_write/ffs_ep0_read get into a race condition\ndue to ep0req being freed up from functionfs_unbind.\n\nConsider the scenario that the ffs_ep0_write calls the ffs_ep0_queue_wait\nby taking a lock &ffs->ev.waitq.lock. However, the functionfs_unbind isn't\nbounded so it can go ahead and mark the ep0req to NULL, and since there\nis no NULL check in ffs_ep0_queue_wait we will end up in use-after-free.\n\nFix this by making a serialized execution between the two functions using\na mutex_lock(ffs->mutex)." } ], "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 race is between local FunctionFS ep0 read/write syscalls and functionfs_unbind during composition switch/gadget teardown, not USB host packet parsing. This matches prior f_fs userspace-API UAF scoring (e.g. CVE-2024-36894, CVE-2025-71074) as Local rather than Physical.\nAC:L - The attacker drives both sides—ep0 I/O into __ffs_ep0_queue_wait and unbind via composition switch or FunctionFS close/unregister—and can retry the race freely. Per guidance, a race the attacker fully creates is AC:L.\nPR:L - FunctionFS mounts commonly use uid=/gid=/fmode= to delegate ep0 to unprivileged gadget daemons (adbd/shell on Android, embedded USB services). Once mounted by init, those accounts can open ep0 and participate in the race without init-namespace root.\nUI:N - The attacker performs ep0 operations and triggers unbind/composition teardown directly; no separate victim action is required beyond an already-deployed FunctionFS gadget.\nS:U - The use-after-free corrupts kernel heap within the same host kernel security authority. This is ordinary local privilege escalation, not a VM escape or IOMMU/sandbox boundary cross.\nC:H - functionfs_unbind frees the live usb_request (ep0req) while __ffs_ep0_queue_wait still uses it; reclaim of that heap object enables attacker-controlled contents and kernel memory disclosure via subsequent field/pointer use.\nI:H - The freed usb_request is written (buf/length/zero) and passed to usb_ep_queue/usb_ep_dequeue, so a reclaimed object yields arbitrary write and control-flow hijack primitives. Kernel UAFs are scored High for integrity.\nA:H - Dereferencing or queuing the freed ep0req (or the concurrently NULLed gadget pointer) causes kernel oops/panic; any such crash 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/function/f_fs.c" ], "versions": [ { "version": "ddf8abd2599491cbad959c700b90ba72a5dce8d0", "lessThan": "facf353c9e8d7885b686d9a4b173d4e0af6441d2", "status": "affected", "versionType": "git" }, { "version": "ddf8abd2599491cbad959c700b90ba72a5dce8d0", "lessThan": "e9036e951f93fb8d7b5e9d6e2c7f94a4da312ae4", "status": "affected", "versionType": "git" }, { "version": "ddf8abd2599491cbad959c700b90ba72a5dce8d0", "lessThan": "a8d40942df074f4ebcb9bd3413596d92f323b064", "status": "affected", "versionType": "git" }, { "version": "ddf8abd2599491cbad959c700b90ba72a5dce8d0", "lessThan": "6dd9ea05534f323668db94fcc2726c7a84547e78", "status": "affected", "versionType": "git" }, { "version": "ddf8abd2599491cbad959c700b90ba72a5dce8d0", "lessThan": "ae8e136bcaae96163b5821984de1036efc9abb1a", "status": "affected", "versionType": "git" }, { "version": "ddf8abd2599491cbad959c700b90ba72a5dce8d0", "lessThan": "6aee197b7fbcd61596a78b47d553f2f99111f217", "status": "affected", "versionType": "git" }, { "version": "ddf8abd2599491cbad959c700b90ba72a5dce8d0", "lessThan": "6a19da111057f69214b97c62fb0ac59023970850", "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/function/f_fs.c" ], "versions": [ { "version": "2.6.35", "status": "affected" }, { "version": "0", "lessThan": "2.6.35", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.305", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.272", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.231", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.166", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.91", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.9", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.2", "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": "2.6.35", "versionEndExcluding": "4.14.305" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "4.19.272" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "5.4.231" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "5.10.166" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "5.15.91" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.1.9" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.2" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/facf353c9e8d7885b686d9a4b173d4e0af6441d2" }, { "url": "https://git.kernel.org/stable/c/e9036e951f93fb8d7b5e9d6e2c7f94a4da312ae4" }, { "url": "https://git.kernel.org/stable/c/a8d40942df074f4ebcb9bd3413596d92f323b064" }, { "url": "https://git.kernel.org/stable/c/6dd9ea05534f323668db94fcc2726c7a84547e78" }, { "url": "https://git.kernel.org/stable/c/ae8e136bcaae96163b5821984de1036efc9abb1a" }, { "url": "https://git.kernel.org/stable/c/6aee197b7fbcd61596a78b47d553f2f99111f217" }, { "url": "https://git.kernel.org/stable/c/6a19da111057f69214b97c62fb0ac59023970850" } ], "title": "usb: gadget: f_fs: Prevent race during ffs_ep0_queue_wait", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2022-49755", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-03-28T15:22:31.876200Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-03-28T15:31:59.379Z" } } ] } }