{"id":"CVE-2026-98764","state":"PUBLISHED","title":"usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC\n\nWhen user space sets up FunctionFS with only full-speed descriptors\n(e.g., flags = FUNCTIONFS_HAS_FS_DESC) and the gadget operates at a\nhigher speed (such as USB_SPEED_HIGH or USB_SPEED_SUPER),\nconfig_ep_by_speed() detects that the function lacks descriptors for\nthe current speed, logs a warning, and falls back to full-speed\ndescriptors. The endpoint is then successfully enabled via\nusb_ep_enable(), and epfile->ep becomes valid.\n\nHowever, when user space subsequently issues the FUNCTIONFS_ENDPOINT_DESC\nioctl to query the endpoint descriptor, ffs_epfile_ioctl() selects the\ndescriptor index solely based on gadget->speed:\n\n\tswitch (epfile->ffs->gadget->speed) {\n\tcase USB_SPEED_SUPER:\n\tcase USB_SPEED_SUPER_PLUS:\n\t\tdesc_idx = 2;\n\t\tbreak;\n\tcase USB_SPEED_HIGH:\n\t\tdesc_idx = 1;\n\t\tbreak;\n\tdefault:\n\t\tdesc_idx = 0;\n\t}\n\tdesc = epfile->ep->descs[desc_idx];\n\tmemcpy(&desc1, desc, desc->bLength);\n\nBecause user space only supplied full-speed descriptors,\nepfile->ep->descs[1] is NULL. Dereferencing desc->bLength triggers an\nimmediate kernel NULL pointer dereference panic.\n\nFix this by falling back through lower speed descriptors if the current\nspeed descriptor was not supplied, matching the fallback logic in\nconfig_ep_by_speed() and historical f_fs behavior. If still missing,\nfall back to epfile->ep->ep->desc (the active descriptor), and return\n-EINVAL safely if no valid descriptor is found. In addition, mark desc\nas const to match struct usb_ep::desc and avoid discarding qualifiers.","publishedAt":"2026-10-18T15:47:56.225Z","updatedAt":"2026-10-30T12:39:33.311Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"c5f452e057df6ef89300523d13ad6833bfd199cd","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"e5b9d6bb2a8906a1188c9a90cc8d102de3f07cad","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"7ef0ad5f462fa95bc4c6647d097d7c0384245b9c","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"06ac8609d6d185ac18c1d6a6a8a9b99e398bd124","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"7811d8e26c77f8eea79e22d0d14c67ec0658b348","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"35ab269602e1f7c4c0fe6ea3477264bea77eced3","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"9cd072788c76595529eb38f42bf94d23852f8534","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_fs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.18","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_fs.c"]}],"references":["https://git.kernel.org/stable/c/c5f452e057df6ef89300523d13ad6833bfd199cd","https://git.kernel.org/stable/c/e5b9d6bb2a8906a1188c9a90cc8d102de3f07cad","https://git.kernel.org/stable/c/7ef0ad5f462fa95bc4c6647d097d7c0384245b9c","https://git.kernel.org/stable/c/06ac8609d6d185ac18c1d6a6a8a9b99e398bd124","https://git.kernel.org/stable/c/9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3","https://git.kernel.org/stable/c/7811d8e26c77f8eea79e22d0d14c67ec0658b348","https://git.kernel.org/stable/c/35ab269602e1f7c4c0fe6ea3477264bea77eced3","https://git.kernel.org/stable/c/9cd072788c76595529eb38f42bf94d23852f8534"],"weaknesses":[],"ingestedAt":"2026-10-30T13:00:06.648Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/98xxx/CVE-2026-98764.json","commit":"cb14bf1b43b0c9f05f7f40eae2246263fd430780","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-98764","state":"PUBLISHED","datePublished":"2026-10-18T15:47:56.225Z","dateUpdated":"2026-10-30T12:39:33.311Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:25:14.368Z"},"containers":{"cna":{"title":"usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC\n\nWhen user space sets up FunctionFS with only full-speed descriptors\n(e.g., flags = FUNCTIONFS_HAS_FS_DESC) and the gadget operates at a\nhigher speed (such as USB_SPEED_HIGH or USB_SPEED_SUPER),\nconfig_ep_by_speed() detects that the function lacks descriptors for\nthe current speed, logs a warning, and falls back to full-speed\ndescriptors. The endpoint is then successfully enabled via\nusb_ep_enable(), and epfile->ep becomes valid.\n\nHowever, when user space subsequently issues the FUNCTIONFS_ENDPOINT_DESC\nioctl to query the endpoint descriptor, ffs_epfile_ioctl() selects the\ndescriptor index solely based on gadget->speed:\n\n\tswitch (epfile->ffs->gadget->speed) {\n\tcase USB_SPEED_SUPER:\n\tcase USB_SPEED_SUPER_PLUS:\n\t\tdesc_idx = 2;\n\t\tbreak;\n\tcase USB_SPEED_HIGH:\n\t\tdesc_idx = 1;\n\t\tbreak;\n\tdefault:\n\t\tdesc_idx = 0;\n\t}\n\tdesc = epfile->ep->descs[desc_idx];\n\tmemcpy(&desc1, desc, desc->bLength);\n\nBecause user space only supplied full-speed descriptors,\nepfile->ep->descs[1] is NULL. Dereferencing desc->bLength triggers an\nimmediate kernel NULL pointer dereference panic.\n\nFix this by falling back through lower speed descriptors if the current\nspeed descriptor was not supplied, matching the fallback logic in\nconfig_ep_by_speed() and historical f_fs behavior. If still missing,\nfall back to epfile->ep->ep->desc (the active descriptor), and return\n-EINVAL safely if no valid descriptor is found. In addition, mark desc\nas const to match struct usb_ep::desc and avoid discarding qualifiers."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"c5f452e057df6ef89300523d13ad6833bfd199cd","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"e5b9d6bb2a8906a1188c9a90cc8d102de3f07cad","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"7ef0ad5f462fa95bc4c6647d097d7c0384245b9c","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"06ac8609d6d185ac18c1d6a6a8a9b99e398bd124","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"7811d8e26c77f8eea79e22d0d14c67ec0658b348","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"35ab269602e1f7c4c0fe6ea3477264bea77eced3","versionType":"git"},{"version":"c559a353410939c0884e83bdb0e2420a986ac53b","status":"affected","lessThan":"9cd072788c76595529eb38f42bf94d23852f8534","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_fs.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"3.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"3.18","versionType":"semver"},{"version":"5.10.273","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.224","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.113","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.56","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.10","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_fs.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/c5f452e057df6ef89300523d13ad6833bfd199cd"},{"url":"https://git.kernel.org/stable/c/e5b9d6bb2a8906a1188c9a90cc8d102de3f07cad"},{"url":"https://git.kernel.org/stable/c/7ef0ad5f462fa95bc4c6647d097d7c0384245b9c"},{"url":"https://git.kernel.org/stable/c/06ac8609d6d185ac18c1d6a6a8a9b99e398bd124"},{"url":"https://git.kernel.org/stable/c/9d8761b3c133f6c6a6d3486839dac60e2cf4bfe3"},{"url":"https://git.kernel.org/stable/c/7811d8e26c77f8eea79e22d0d14c67ec0658b348"},{"url":"https://git.kernel.org/stable/c/35ab269602e1f7c4c0fe6ea3477264bea77eced3"},{"url":"https://git.kernel.org/stable/c/9cd072788c76595529eb38f42bf94d23852f8534"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:39:33.311Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"5.10.273"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"5.15.224"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.12.113"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"6.18.56"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"7.2.10"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.18","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}