{"id":"CVE-2023-52894","state":"PUBLISHED","title":"usb: gadget: f_ncm: fix potential NULL ptr deref in ncm_bitrate()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_ncm: fix potential NULL ptr deref in ncm_bitrate()\n\nIn Google internal bug 265639009 we've received an (as yet) unreproducible\ncrash report from an aarch64 GKI 5.10.149-android13 running device.\n\nAFAICT the source code is at:\n  https://android.googlesource.com/kernel/common/+/refs/tags/ASB-2022-12-05_13-5.10\n\nThe call stack is:\n  ncm_close() -> ncm_notify() -> ncm_do_notify()\nwith the crash at:\n  ncm_do_notify+0x98/0x270\nCode: 79000d0b b9000a6c f940012a f9400269 (b9405d4b)\n\nWhich I believe disassembles to (I don't know ARM assembly, but it looks sane enough to me...):\n\n  // halfword (16-bit) store presumably to event->wLength (at offset 6 of struct usb_cdc_notification)\n  0B 0D 00 79    strh w11, [x8, #6]\n\n  // word (32-bit) store presumably to req->Length (at offset 8 of struct usb_request)\n  6C 0A 00 B9    str  w12, [x19, #8]\n\n  // x10 (NULL) was read here from offset 0 of valid pointer x9\n  // IMHO we're reading 'cdev->gadget' and getting NULL\n  // gadget is indeed at offset 0 of struct usb_composite_dev\n  2A 01 40 F9    ldr  x10, [x9]\n\n  // loading req->buf pointer, which is at offset 0 of struct usb_request\n  69 02 40 F9    ldr  x9, [x19]\n\n  // x10 is null, crash, appears to be attempt to read cdev->gadget->max_speed\n  4B 5D 40 B9    ldr  w11, [x10, #0x5c]\n\nwhich seems to line up with ncm_do_notify() case NCM_NOTIFY_SPEED code fragment:\n\n  event->wLength = cpu_to_le16(8);\n  req->length = NCM_STATUS_BYTECOUNT;\n\n  /* SPEED_CHANGE data is up/down speeds in bits/sec */\n  data = req->buf + sizeof *event;\n  data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget));\n\nMy analysis of registers and NULL ptr deref crash offset\n  (Unable to handle kernel NULL pointer dereference at virtual address 000000000000005c)\nheavily suggests that the crash is due to 'cdev->gadget' being NULL when executing:\n  data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget));\nwhich calls:\n  ncm_bitrate(NULL)\nwhich then calls:\n  gadget_is_superspeed(NULL)\nwhich reads\n  ((struct usb_gadget *)NULL)->max_speed\nand hits a panic.\n\nAFAICT, if I'm counting right, the offset of max_speed is indeed 0x5C.\n(remember there's a GKI KABI reservation of 16 bytes in struct work_struct)\n\nIt's not at all clear to me how this is all supposed to work...\nbut returning 0 seems much better than panic-ing...","publishedAt":"2024-08-21T06:10:34.120Z","updatedAt":"2026-05-11T19:35:02.622Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"fef6b29671b66dfb71f17e337c1ad14b5a2cedae","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"63d161f29cd39c050e8873aa36e0c9fc013bb763","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"a21da7f7aae618c785f7e4a275d43c06dc8412b6","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"e92c70059178da751e5af7de02384b7dfadb5ec7","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"a69c8dfb85b44be9cc223be07d35cc3a9baefbea","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"09e4507ec8ef2d44da6ba4092b8ee2d81f216497","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"c6ec929595c7443250b2a4faea988c62019d5cd2","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_ncm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.9","versionType":"semver"},{"version":"4.14.304","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.271","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.230","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.165","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.90","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.8","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2","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_ncm.c"]}],"references":["https://git.kernel.org/stable/c/fef6b29671b66dfb71f17e337c1ad14b5a2cedae","https://git.kernel.org/stable/c/63d161f29cd39c050e8873aa36e0c9fc013bb763","https://git.kernel.org/stable/c/a21da7f7aae618c785f7e4a275d43c06dc8412b6","https://git.kernel.org/stable/c/e92c70059178da751e5af7de02384b7dfadb5ec7","https://git.kernel.org/stable/c/a69c8dfb85b44be9cc223be07d35cc3a9baefbea","https://git.kernel.org/stable/c/09e4507ec8ef2d44da6ba4092b8ee2d81f216497","https://git.kernel.org/stable/c/c6ec929595c7443250b2a4faea988c62019d5cd2"],"weaknesses":[],"ingestedAt":"2026-10-29T20:06:33.064Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/52xxx/CVE-2023-52894.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-52894","state":"PUBLISHED","datePublished":"2024-08-21T06:10:34.120Z","dateUpdated":"2026-05-11T19:35:02.622Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-08-21T06:07:11.013Z"},"containers":{"cna":{"title":"usb: gadget: f_ncm: fix potential NULL ptr deref in ncm_bitrate()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: gadget: f_ncm: fix potential NULL ptr deref in ncm_bitrate()\n\nIn Google internal bug 265639009 we've received an (as yet) unreproducible\ncrash report from an aarch64 GKI 5.10.149-android13 running device.\n\nAFAICT the source code is at:\n  https://android.googlesource.com/kernel/common/+/refs/tags/ASB-2022-12-05_13-5.10\n\nThe call stack is:\n  ncm_close() -> ncm_notify() -> ncm_do_notify()\nwith the crash at:\n  ncm_do_notify+0x98/0x270\nCode: 79000d0b b9000a6c f940012a f9400269 (b9405d4b)\n\nWhich I believe disassembles to (I don't know ARM assembly, but it looks sane enough to me...):\n\n  // halfword (16-bit) store presumably to event->wLength (at offset 6 of struct usb_cdc_notification)\n  0B 0D 00 79    strh w11, [x8, #6]\n\n  // word (32-bit) store presumably to req->Length (at offset 8 of struct usb_request)\n  6C 0A 00 B9    str  w12, [x19, #8]\n\n  // x10 (NULL) was read here from offset 0 of valid pointer x9\n  // IMHO we're reading 'cdev->gadget' and getting NULL\n  // gadget is indeed at offset 0 of struct usb_composite_dev\n  2A 01 40 F9    ldr  x10, [x9]\n\n  // loading req->buf pointer, which is at offset 0 of struct usb_request\n  69 02 40 F9    ldr  x9, [x19]\n\n  // x10 is null, crash, appears to be attempt to read cdev->gadget->max_speed\n  4B 5D 40 B9    ldr  w11, [x10, #0x5c]\n\nwhich seems to line up with ncm_do_notify() case NCM_NOTIFY_SPEED code fragment:\n\n  event->wLength = cpu_to_le16(8);\n  req->length = NCM_STATUS_BYTECOUNT;\n\n  /* SPEED_CHANGE data is up/down speeds in bits/sec */\n  data = req->buf + sizeof *event;\n  data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget));\n\nMy analysis of registers and NULL ptr deref crash offset\n  (Unable to handle kernel NULL pointer dereference at virtual address 000000000000005c)\nheavily suggests that the crash is due to 'cdev->gadget' being NULL when executing:\n  data[0] = cpu_to_le32(ncm_bitrate(cdev->gadget));\nwhich calls:\n  ncm_bitrate(NULL)\nwhich then calls:\n  gadget_is_superspeed(NULL)\nwhich reads\n  ((struct usb_gadget *)NULL)->max_speed\nand hits a panic.\n\nAFAICT, if I'm counting right, the offset of max_speed is indeed 0x5C.\n(remember there's a GKI KABI reservation of 16 bytes in struct work_struct)\n\nIt's not at all clear to me how this is all supposed to work...\nbut returning 0 seems much better than panic-ing..."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"fef6b29671b66dfb71f17e337c1ad14b5a2cedae","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"63d161f29cd39c050e8873aa36e0c9fc013bb763","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"a21da7f7aae618c785f7e4a275d43c06dc8412b6","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"e92c70059178da751e5af7de02384b7dfadb5ec7","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"a69c8dfb85b44be9cc223be07d35cc3a9baefbea","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"09e4507ec8ef2d44da6ba4092b8ee2d81f216497","versionType":"git"},{"version":"1650113888fe7b7e16604a5019c32dd3ddeb3af2","status":"affected","lessThan":"c6ec929595c7443250b2a4faea988c62019d5cd2","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/gadget/function/f_ncm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.9","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.9","versionType":"semver"},{"version":"4.14.304","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.271","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.230","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.165","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.90","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.8","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.2","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_ncm.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/fef6b29671b66dfb71f17e337c1ad14b5a2cedae"},{"url":"https://git.kernel.org/stable/c/63d161f29cd39c050e8873aa36e0c9fc013bb763"},{"url":"https://git.kernel.org/stable/c/a21da7f7aae618c785f7e4a275d43c06dc8412b6"},{"url":"https://git.kernel.org/stable/c/e92c70059178da751e5af7de02384b7dfadb5ec7"},{"url":"https://git.kernel.org/stable/c/a69c8dfb85b44be9cc223be07d35cc3a9baefbea"},{"url":"https://git.kernel.org/stable/c/09e4507ec8ef2d44da6ba4092b8ee2d81f216497"},{"url":"https://git.kernel.org/stable/c/c6ec929595c7443250b2a4faea988c62019d5cd2"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T19:35:02.622Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"4.14.304"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"4.19.271"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"5.4.230"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"5.10.165"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"5.15.90"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"6.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"6.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2023-52894","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-09-10T16:03:50.056364Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2024-09-12T17:33:13.931Z"}}]}}}