In the Linux kernel, the following vulnerability has been resolved:
bpf: Check the remaining info_cnt before repeating btf fields
When trying to repeat the btf fields for array of nested struct, it doesn't check the remaining info_cnt. The following splat will be reported when the value of ret * nelems is greater than BTF_FIELDS_MAX:
------------[ cut here ]------------ UBSAN: array-index-out-of-bounds in ../kernel/bpf/btf.c:3951:49 index 11 is out of range for type 'btf_field_info [11]' CPU: 6 UID: 0 PID: 411 Comm: test_progs ...... 6.11.0-rc4+ #1 Tainted: [O]=OOT_MODULE Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ... Call Trace: <TASK> dump_stack_lvl+0x57/0x70 dump_stack+0x10/0x20 ubsan_epilogue+0x9/0x40 __ubsan_handle_out_of_bounds+0x6f/0x80 ? kallsyms_lookup_name+0x48/0xb0 btf_parse_fields+0x992/0xce0 map_create+0x591/0x770 __sys_bpf+0x229/0x2410 __x64_sys_bpf+0x1f/0x30 x64_sys_call+0x199/0x9f0 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x7fea56f2cc5d ...... </TASK> ---[ end trace ]---
Fix it by checking the remaining info_cnt in btf_repeat_fields() before repeating the btf fields.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade linux | Jul 27, 2026 | Jul 27, 2026 |
| Ubuntu | — | Upgrade linux-image-genericUpgrade linux-image-lowlatency-64kUpgrade linux-image-6.11.0-1008-raspiUpgrade linux-image-oracleUpgrade linux-image-6.11.0-18-generic-64kUpgrade linux-image-lowlatencyUpgrade linux-image-6.11.0-1009-awsUpgrade linux-image-oem-24.04Upgrade linux-image-6.11.0-1009-azureUpgrade linux-image-6.11.0-1009-azure-fdeUpgrade linux-image-6.11.0-1009-gcpUpgrade linux-image-generic-64kUpgrade linux-image-oem-24.04bUpgrade linux-image-oem-24.04aUpgrade linux-image-generic-64k-hwe-24.04Upgrade linux-image-oracle-64kUpgrade linux-image-raspiUpgrade linux-image-generic-hwe-24.04Upgrade linux-image-6.11.0-1015-oemUpgrade linux-image-6.11.0-1010-lowlatency-64kUpgrade linux-image-6.11.0-1011-oracle-64kUpgrade linux-image-6.11.0-1010-lowlatencyUpgrade linux-image-realtimeUpgrade linux-image-virtual-hwe-24.04Upgrade linux-image-6.11.0-1011-oracleUpgrade linux-image-azure-fdeUpgrade linux-image-6.11.0-18-genericUpgrade linux-image-virtualUpgrade linux-image-awsUpgrade linux-image-realtime-hwe-24.04Upgrade linux-image-gcpUpgrade linux-image-azureUpgrade linux-image-6.11.0-1005-realtime | Feb 20, 2025 | Nov 7, 2024 |
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