CVE-2026-90055

CVE CVE-2026-90055EUVD EUVD-2026-81916Published 2026-09-17T16:05:40.000Z

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: usb: atm: usbatm: fix invalid ci_range initialization syzbot reported a shift-out-of-bounds in __vcc_connect(): UBSAN: shift-out-of-bounds in net/atm/common.c:382:32 shift exponent -1 is negative CPU: 0 UID: 0 PID: 5987 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 08/05/2026 Call Trace: <TASK> dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233 __ubsan_handle_shift_out_of_bounds+0x36d/0x400 lib/ubsan.c:494 __vcc_connect+0x14b4/0x19c0 net/atm/common.c:382 vcc_connect+0x328/0x8f0 net/atm/common.c:498 pvc_bind+0x272/0x380 net/atm/pvc.c:52 __sys_bind+0x2e3/0x410 net/socket.c:1976 __x64_sys_bind+0x7a/0x90 net/socket.c:1979 ... ATM device ci_range fields (vpi_bits and vci_bits) represent the number of bits supported for VPI and VCI addressing on the device. net/atm/common.c directly uses these fields as bit shift counts: vpi >> dev->ci_range.vpi_bits vci >> dev->ci_range.vci_bits 1 << vcc->dev->ci_range.vpi_bits 1 << vcc->dev->ci_range.vci_bits usbatm_atm_init() sets ci_range.vpi_bits and ci_range.vci_bits to ATM_CI_MAX (-1), which is defined in <uapi/linux/atmdev.h> as a sentinel value for userspace ATM_SETCIRANGE requests, not a valid bit count. Shifting by -1 is undefined behavior and triggers UBSAN warnings. ATM UNI cell headers allow up to 8 bits for VPI (0..255) and 16 bits for VCI (0..65535). Initialize vpi_bits to 8 and vci_bits to 16, as done by solos-pci.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux patch: 7.2.6; c59bba75fa500f13ef14215d599ee0d7faa1b954 <8442586526c406527bf31206e538c0ce6bc672e6; patch: 0; patch: 6.18.52; c59bba75fa500f13ef14215d599ee0d7faa1b954 <76bc7c3a44856744b64aa91d9afe6d9522a78c42; c59bba75fa500f13ef14215d599ee0d7faa1b954 <ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c; c59bba75fa500f13ef14215d599ee0d7faa1b954 <a60fd8c6dbaa76da4163cf225ed2b9e982540f39; patch: 5.15.221; c59bba75fa500f13ef14215d599ee0d7faa1b954 <7baa0c92be39eb3da755ed6f200497a57078c47b; 2.6.13; patch: 6.1.188; patch: 6.12.110; c59bba75fa500f13ef14215d599ee0d7faa1b954 <1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422; c59bba75fa500f13ef14215d599ee0d7faa1b954 <561cbd6d49022c9a383e22a39c87a165a4d39f9c; patch: 6.6.157; patch: 7.3-rc1; c59bba75fa500f13ef14215d599ee0d7faa1b954 <75667703115154a4fd9cf259d4f826d8729cbcda; patch: 5.10.270

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

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