cbcvebase.
CVE-2026-45839
published 2026-05-27

CVE-2026-45839: 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…

PriorityP340high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.13%
3.2th percentile
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 >= 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) >= (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: 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) CO-RE accessor indices are inherently non-negative (struct member index, array element index, or enumerator index), so reject them immediately after parsing.

Affected

44 ranges· showing 25
VendorProductVersion rangeFixed in
linuxlinux
linuxlinux>= ddc7c3042614e273044f698d2beab25cc3842d45 < a9e777f856cd2f1efc106afc7bf21aef868509d5a9e777f856cd2f1efc106afc7bf21aef868509d5
linuxlinux>= ddc7c3042614e273044f698d2beab25cc3842d45 < 669349b4612c26b3d7aacfa99d7174681bd19223669349b4612c26b3d7aacfa99d7174681bd19223
linuxlinux>= ddc7c3042614e273044f698d2beab25cc3842d45 < 3ff85ae79e1a74baeb916b78a63d821f6d19a9943ff85ae79e1a74baeb916b78a63d821f6d19a994
linuxlinux>= ddc7c3042614e273044f698d2beab25cc3842d45 < 36a9012f76ba8d9189ae56a1f8bb7c87c07a1f3a36a9012f76ba8d9189ae56a1f8bb7c87c07a1f3a
linuxlinux>= ddc7c3042614e273044f698d2beab25cc3842d45 < 76f2ebaf79a9ae6d0737b87f045fe769e425d78f76f2ebaf79a9ae6d0737b87f045fe769e425d78f
linuxlinux>= ddc7c3042614e273044f698d2beab25cc3842d45 < 99dbab7b5a12d8f58d5b0aa2f7a1fe656a70f4b299dbab7b5a12d8f58d5b0aa2f7a1fe656a70f4b2
linuxlinux>= ddc7c3042614e273044f698d2beab25cc3842d45 < 1c22483a2c4bbf747787f328392ca3e68619c4dc1c22483a2c4bbf747787f328392ca3e68619c4dc
linuxlinux_kernel>= 5.16 < 6.1.1756.1.175
linuxlinux_kernel>= 5.4 < 5.15.2095.15.209
linuxlinux_kernel>= 6.13 < 6.18.336.18.33
linuxlinux_kernel>= 6.19 < 7.0.107.0.10
linuxlinux_kernel>= 6.2 < 6.6.1416.6.141
linuxlinux_kernel>= 6.7 < 6.12.916.12.91
ubuntulinux
ubuntulinux-aws
ubuntulinux-aws-5.15
ubuntulinux-aws-fips
ubuntulinux-fips
ubuntulinux-gcp
ubuntulinux-gcp-6.8
ubuntulinux-gcp-fips
ubuntulinux-gke
ubuntulinux-gkeop
ubuntulinux-hwe-5.15

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
vendor_ubuntu7.1HIGH
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