{"id":"CVE-2026-90055","state":"PUBLISHED","title":"usb: atm: usbatm: fix invalid ci_range initialization","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: atm: usbatm: fix invalid ci_range initialization\n\nsyzbot reported a shift-out-of-bounds in __vcc_connect():\n\n  UBSAN: shift-out-of-bounds in net/atm/common.c:382:32\n  shift exponent -1 is negative\n  CPU: 0 UID: 0 PID: 5987 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full)\n  Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120\n   ubsan_epilogue+0xa/0x30 lib/ubsan.c:233\n   __ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494\n   __vcc_connect+0x14b4/0x19c0 net/atm/common.c:382\n   vcc_connect+0x328/0x8f0 net/atm/common.c:498\n   pvc_bind+0x272/0x380 net/atm/pvc.c:52\n   __sys_bind+0x2e3/0x410 net/socket.c:1976\n   __x64_sys_bind+0x7a/0x90 net/socket.c:1979\n   ...\n\nATM device ci_range fields (vpi_bits and vci_bits) represent the\nnumber of bits supported for VPI and VCI addressing on the device.\nnet/atm/common.c directly uses these fields as bit shift counts:\n  vpi >> dev->ci_range.vpi_bits\n  vci >> dev->ci_range.vci_bits\n  1 << vcc->dev->ci_range.vpi_bits\n  1 << vcc->dev->ci_range.vci_bits\n\nusbatm_atm_init() sets ci_range.vpi_bits and ci_range.vci_bits to\nATM_CI_MAX (-1), which is defined in <uapi/linux/atmdev.h> as a\nsentinel value for userspace ATM_SETCIRANGE requests, not a valid bit\ncount. Shifting by -1 is undefined behavior and triggers UBSAN\nwarnings.\n\nATM UNI cell headers allow up to 8 bits for VPI (0..255) and 16 bits\nfor VCI (0..65535). Initialize vpi_bits to 8 and vci_bits to 16, as\ndone by solos-pci.","publishedAt":"2026-09-17T16:05:40.304Z","updatedAt":"2026-10-19T08:57:12.606Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"8442586526c406527bf31206e538c0ce6bc672e6","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"561cbd6d49022c9a383e22a39c87a165a4d39f9c","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"76bc7c3a44856744b64aa91d9afe6d9522a78c42","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"7baa0c92be39eb3da755ed6f200497a57078c47b","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"75667703115154a4fd9cf259d4f826d8729cbcda","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"a60fd8c6dbaa76da4163cf225ed2b9e982540f39","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/atm/usbatm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.13","versionType":"semver"},{"version":"5.10.270","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","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/atm/usbatm.c"]}],"references":["https://git.kernel.org/stable/c/8442586526c406527bf31206e538c0ce6bc672e6","https://git.kernel.org/stable/c/561cbd6d49022c9a383e22a39c87a165a4d39f9c","https://git.kernel.org/stable/c/76bc7c3a44856744b64aa91d9afe6d9522a78c42","https://git.kernel.org/stable/c/7baa0c92be39eb3da755ed6f200497a57078c47b","https://git.kernel.org/stable/c/1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422","https://git.kernel.org/stable/c/ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c","https://git.kernel.org/stable/c/75667703115154a4fd9cf259d4f826d8729cbcda","https://git.kernel.org/stable/c/a60fd8c6dbaa76da4163cf225ed2b9e982540f39"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90055.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90055","state":"PUBLISHED","datePublished":"2026-09-17T16:05:40.304Z","dateUpdated":"2026-10-19T08:57:12.606Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-11T19:38:34.783Z"},"containers":{"cna":{"title":"usb: atm: usbatm: fix invalid ci_range initialization","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: atm: usbatm: fix invalid ci_range initialization\n\nsyzbot reported a shift-out-of-bounds in __vcc_connect():\n\n  UBSAN: shift-out-of-bounds in net/atm/common.c:382:32\n  shift exponent -1 is negative\n  CPU: 0 UID: 0 PID: 5987 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full)\n  Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120\n   ubsan_epilogue+0xa/0x30 lib/ubsan.c:233\n   __ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494\n   __vcc_connect+0x14b4/0x19c0 net/atm/common.c:382\n   vcc_connect+0x328/0x8f0 net/atm/common.c:498\n   pvc_bind+0x272/0x380 net/atm/pvc.c:52\n   __sys_bind+0x2e3/0x410 net/socket.c:1976\n   __x64_sys_bind+0x7a/0x90 net/socket.c:1979\n   ...\n\nATM device ci_range fields (vpi_bits and vci_bits) represent the\nnumber of bits supported for VPI and VCI addressing on the device.\nnet/atm/common.c directly uses these fields as bit shift counts:\n  vpi >> dev->ci_range.vpi_bits\n  vci >> dev->ci_range.vci_bits\n  1 << vcc->dev->ci_range.vpi_bits\n  1 << vcc->dev->ci_range.vci_bits\n\nusbatm_atm_init() sets ci_range.vpi_bits and ci_range.vci_bits to\nATM_CI_MAX (-1), which is defined in <uapi/linux/atmdev.h> as a\nsentinel value for userspace ATM_SETCIRANGE requests, not a valid bit\ncount. Shifting by -1 is undefined behavior and triggers UBSAN\nwarnings.\n\nATM UNI cell headers allow up to 8 bits for VPI (0..255) and 16 bits\nfor VCI (0..65535). Initialize vpi_bits to 8 and vci_bits to 16, as\ndone by solos-pci."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"8442586526c406527bf31206e538c0ce6bc672e6","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"561cbd6d49022c9a383e22a39c87a165a4d39f9c","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"76bc7c3a44856744b64aa91d9afe6d9522a78c42","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"7baa0c92be39eb3da755ed6f200497a57078c47b","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"75667703115154a4fd9cf259d4f826d8729cbcda","versionType":"git"},{"version":"c59bba75fa500f13ef14215d599ee0d7faa1b954","status":"affected","lessThan":"a60fd8c6dbaa76da4163cf225ed2b9e982540f39","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/usb/atm/usbatm.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.13","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.13","versionType":"semver"},{"version":"5.10.270","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.221","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.188","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.157","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.110","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.52","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.6","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/atm/usbatm.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/8442586526c406527bf31206e538c0ce6bc672e6"},{"url":"https://git.kernel.org/stable/c/561cbd6d49022c9a383e22a39c87a165a4d39f9c"},{"url":"https://git.kernel.org/stable/c/76bc7c3a44856744b64aa91d9afe6d9522a78c42"},{"url":"https://git.kernel.org/stable/c/7baa0c92be39eb3da755ed6f200497a57078c47b"},{"url":"https://git.kernel.org/stable/c/1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422"},{"url":"https://git.kernel.org/stable/c/ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c"},{"url":"https://git.kernel.org/stable/c/75667703115154a4fd9cf259d4f826d8729cbcda"},{"url":"https://git.kernel.org/stable/c/a60fd8c6dbaa76da4163cf225ed2b9e982540f39"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T08:57:12.606Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"5.10.270"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"5.15.221"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.1.188"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.6.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.12.110"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"6.18.52"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"7.2.6"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.13","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}