CVE-2026-93121

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-93121", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-17T16:02:15.086Z", "datePublished": "2026-09-17T16:11:27.220Z", "dateUpdated": "2026-10-19T09:05:54.766Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:05:54.766Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix fence cleanup in ffs_dmabuf_transfer() error paths\n\nThe error paths for endpoint-disabled (ESHUTDOWN) and request-allocation\nfailure (ENOMEM) in ffs_dmabuf_transfer() jump to err_fence_put which\ncalls dma_fence_put() on the fence. However, at that point the fence has\nonly been kmalloc'd \u2014 dma_fence_init() has not been called yet, so the\nrefcount and the fence ops are uninitialized. Calling dma_fence_put() on\nsuch an object leads to undefined behavior.\n\nUse kfree() instead, since the fence is just a plain allocation at this\nstage, and rename the label to err_fence_free to reflect the actual\ncleanup action."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The uninitialized fence is kmalloc'd and then dma_fence_put() in ffs_dmabuf_transfer(), reached only from ffs_epfile_ioctl()'s FUNCTIONFS_DMABUF_TRANSFER case after copy_from_user of usb_ffs_dmabuf_transfer_req; USB host traffic never supplies that ioctl or the fence object.\nAC:H - err_fence_put runs only when epfile->ep != ep after ffs_epfile_wait_ep() (epfile->ep is NULLed solely by ffs_func_eps_disable() from gadget set_alt/disable/unbind) or when usb_ep_alloc_request(..., GFP_ATOMIC) fails; the ioctl caller cannot invoke those gadget callbacks and cannot reliably force that small GFP_ATOMIC allocation to fail.\nPR:L - ffs_epfile_ioctl() has no capable() check; FUNCTIONFS_DMABUF_TRANSFER only needs the endpoint file open. FunctionFS inodes take uid/gid/mode from ffs_fs_parse_param() (uid=/gid=/fmode=), which deployed gadgets use to hand ep nodes to non-root daemons such as adbd.\nUI:N - The attacker issues FUNCTIONFS_DMABUF_TRANSFER themselves on an endpoint fd they already hold; ffs_epfile_wait_ep() needing a prior host SET_CONFIGURATION is ambient gadget enumeration, not a victim action at exploit time.\nS:U - dma_fence_put() on the kmalloc'd ffs_dma_fence runs dma_fence_release() in the same kernel that hosts FunctionFS, so impact stays inside that kernel's privilege boundary rather than crossing a VM or IOMMU authority.\nC:H - kmalloc_obj(*fence) is not zeroed and dma_fence_init() has not run, so fence->refcount and fence->ops are leftover heap contents; dma_fence_put() calls dma_fence_release() if the sprayed refcount is 1, which rcu_dereference()s ops and reads other fence fields.\nI:H - dma_fence_release() calls ops->release() through the uninitialized fence->ops pointer (or walks garbage cb_list in the pending-signal path); a same-cache heap spray can point ops at attacker-controlled function pointers for control-flow hijack.\nA:H - dma_fence_release() does list_empty(&fence->cb_list) and dma_fence_lock_irqsave() on uninitialized cb_list/lock and may invoke a wild ops->release(), any of which oopses or panics when the ESHUTDOWN or ENOMEM err_fence_put path runs."}]}], "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": "7b07a2a7ca02a20124b552be96c5a56910795488", "lessThan": "be539138d9a187af3b884525a395db10797c64f1", "status": "affected", "versionType": "git"}, {"version": "7b07a2a7ca02a20124b552be96c5a56910795488", "lessThan": "5fd8baacc7dc477df9cac61b45491840247a9b1e", "status": "affected", "versionType": "git"}, {"version": "7b07a2a7ca02a20124b552be96c5a56910795488", "lessThan": "58952c83dfe6ea3294a74734d2d1018c1120779a", "status": "affected", "versionType": "git"}, {"version": "7b07a2a7ca02a20124b552be96c5a56910795488", "lessThan": "621707dc67c9846fd876d7579ec951d92aa033f1", "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": "6.9", "status": "affected"}, {"version": "0", "lessThan": "6.9", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.6", "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": "6.9", "versionEndExcluding": "6.12.110"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "6.18.52"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.2.6"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.9", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/be539138d9a187af3b884525a395db10797c64f1"}, {"url": "https://git.kernel.org/stable/c/5fd8baacc7dc477df9cac61b45491840247a9b1e"}, {"url": "https://git.kernel.org/stable/c/58952c83dfe6ea3294a74734d2d1018c1120779a"}, {"url": "https://git.kernel.org/stable/c/621707dc67c9846fd876d7579ec951d92aa033f1"}], "title": "usb: gadget: f_fs: Fix fence cleanup in ffs_dmabuf_transfer() error paths", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/usb/gadget/function/f_fs.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "be539138d9a187af3b884525a395db10797c64f1", "status": "affected", "version": "7b07a2a7ca02a20124b552be96c5a56910795488", "versionType": "git"}, {"lessThan": "5fd8baacc7dc477df9cac61b45491840247a9b1e", "status": "affected", "version": "7b07a2a7ca02a20124b552be96c5a56910795488", "versionType": "git"}, {"lessThan": "58952c83dfe6ea3294a74734d2d1018c1120779a", "status": "affected", "version": "7b07a2a7ca02a20124b552be96c5a56910795488", "versionType": "git"}, {"lessThan": "621707dc67c9846fd876d7579ec951d92aa033f1", "status": "affected", "version": "7b07a2a7ca02a20124b552be96c5a56910795488", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/usb/gadget/function/f_fs.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.9"}, {"lessThan": "6.9", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.110", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.52", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.6", "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: f_fs: Fix fence cleanup in ffs_dmabuf_transfer() error paths\n\nThe error paths for endpoint-disabled (ESHUTDOWN) and request-allocation\nfailure (ENOMEM) in ffs_dmabuf_transfer() jump to err_fence_put which\ncalls dma_fence_put() on the fence. However, at that point the fence has\nonly been kmalloc'd \u2014 dma_fence_init() has not been called yet, so the\nrefcount and the fence ops are uninitialized. Calling dma_fence_put() on\nsuch an object leads to undefined behavior.\n\nUse kfree() instead, since the fence is just a plain allocation at this\nstage, and rename the label to err_fence_free to reflect the actual\ncleanup action."}], "id": "CVE-2026-93121", "lastModified": "2026-10-19T10:17:02.090", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.0, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.0, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-09-17T17:18:06.803", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/58952c83dfe6ea3294a74734d2d1018c1120779a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5fd8baacc7dc477df9cac61b45491840247a9b1e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/621707dc67c9846fd876d7579ec951d92aa033f1"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/be539138d9a187af3b884525a395db10797c64f1"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[7b07a2a7ca02a20124b552be96c5a56910795488,be539138d9a187af3b884525a395db10797c64f1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[7b07a2a7ca02a20124b552be96c5a56910795488,5fd8baacc7dc477df9cac61b45491840247a9b1e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[7b07a2a7ca02a20124b552be96c5a56910795488,58952c83dfe6ea3294a74734d2d1018c1120779a)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[7b07a2a7ca02a20124b552be96c5a56910795488,621707dc67c9846fd876d7579ec951d92aa033f1)"}}], "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": "6.9"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.9)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.110,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.52,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.6,7.3.0)"}}, {"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": "2026-09-19T09:00:14.733941+00:00", "updated": "2026-09-20T06:00:13.765514+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-457"]}