{"id":"DEBIAN-CVE-2026-45839","details":"In the Linux kernel, the following vulnerability has been resolved:  bpf: reject negative CO-RE accessor indices in bpf_core_parse_spec()  CO-RE accessor strings are colon-separated indices that describe a path from a root BTF type to a target field, e.g. \"0:1:2\" walks through nested struct members. bpf_core_parse_spec() parses each component with sscanf(\"%d\"), so negative values like -1 are silently accepted.  The subsequent bounds checks (access_idx \u003e= btf_vlen(t)) only guard the upper bound and always pass for negative values because C integer promotion converts the __u16 btf_vlen result to int, making the comparison (int)(-1) \u003e= (int)(N) false for any positive N.  When -1 reaches btf_member_bit_offset() it gets cast to u32 0xffffffff, producing an out-of-bounds read far past the members array.  A crafted BPF program with a negative CO-RE accessor on any struct that exists in vmlinux BTF (e.g. task_struct) crashes the kernel deterministically during BPF_PROG_LOAD on any system with CONFIG_DEBUG_INFO_BTF=y (default on major distributions).  The bug is reachable with CAP_BPF:   BUG: unable to handle page fault for address: ffffed11818b6626  #PF: supervisor read access in kernel mode  #PF: error_code(0x0000) - not-present page  Oops: Oops: 0000 [#1] SMP KASAN NOPTI  CPU: 0 UID: 0 PID: 85 Comm: poc Not tainted 7.0.0-rc6 #18 PREEMPT(full)  RIP: 0010:bpf_core_parse_spec (tools/lib/bpf/relo_core.c:354)  RAX: 00000000ffffffff  Call Trace:   \u003cTASK\u003e   bpf_core_calc_relo_insn (tools/lib/bpf/relo_core.c:1321)   bpf_core_apply (kernel/bpf/btf.c:9507)   check_core_relo (kernel/bpf/verifier.c:19475)   bpf_check (kernel/bpf/verifier.c:26031)   bpf_prog_load (kernel/bpf/syscall.c:3089)   __sys_bpf (kernel/bpf/syscall.c:6228)   \u003c/TASK\u003e  CO-RE accessor indices are inherently non-negative (struct member index, array element index, or enumerator index), so reject them immediately after parsing.","modified":"2026-09-01T16:06:45.397656221Z","published":"2026-05-27T11:16:23.247Z","upstream":["CVE-2026-45839"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2026-45839"}],"affected":[{"package":{"name":"linux","ecosystem":"Debian:12","purl":"pkg:deb/debian/linux?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.1.176-1"}]}],"versions":["6.1.106-1","6.1.106-2","6.1.106-3","6.1.112-1","6.1.115-1","6.1.119-1","6.1.123-1","6.1.124-1","6.1.128-1","6.1.129-1","6.1.133-1","6.1.135-1","6.1.137-1","6.1.139-1","6.1.140-1","6.1.147-1","6.1.148-1","6.1.153-1","6.1.158-1","6.1.159-1","6.1.162-1","6.1.164-1","6.1.170-1","6.1.170-2","6.1.170-3","6.1.172-1","6.1.174-1","6.1.27-1","6.1.37-1","6.1.38-1","6.1.38-2","6.1.38-2~bpo11+1","6.1.38-3","6.1.38-4","6.1.38-4~bpo11+1","6.1.52-1","6.1.55-1","6.1.55-1~bpo11+1","6.1.64-1","6.1.66-1","6.1.67-1","6.1.69-1","6.1.69-1~bpo11+1","6.1.76-1","6.1.76-1~bpo11+1","6.1.82-1","6.1.85-1","6.1.90-1","6.1.90-1~bpo11+1","6.1.94-1","6.1.94-1~bpo11+1","6.1.98-1","6.1.99-1"],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2026-45839.json"}},{"package":{"name":"linux","ecosystem":"Debian:13","purl":"pkg:deb/debian/linux?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.12.94-1"}]}],"versions":["6.12.38-1","6.12.41-1","6.12.43-1","6.12.43-1~bpo12+1","6.12.48-1","6.12.57-1","6.12.57-1~bpo12+1","6.12.63-1","6.12.63-1~bpo12+1","6.12.69-1","6.12.69-1~bpo12+1","6.12.73-1","6.12.73-1~bpo12+1","6.12.74-1","6.12.74-2","6.12.74-2~bpo12+1","6.12.85-1","6.12.85-1~bpo12+1","6.12.86-1","6.12.86-1~bpo12+1","6.12.88-1","6.12.88-1~bpo12+1","6.12.90-1","6.12.90-1~bpo12+1","6.12.90-2","6.12.90-2~bpo12+1","6.12.94-1~bpo12+1"],"ecosystem_specific":{"urgency":"not yet 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