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:
<TASK>
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)
</TASK>
CO-RE accessor indices are inherently non-negative (struct member index,
array element index, or enumerator index), so reject them immediately
after parsing.
References
Configurations
Configuration 1 (hide)
|
History
26 Jun 2026, 19:08
| Type | Values Removed | Values Added |
|---|---|---|
| CWE | CWE-129 | |
| References | () https://git.kernel.org/stable/c/1c22483a2c4bbf747787f328392ca3e68619c4dc - Patch | |
| References | () https://git.kernel.org/stable/c/36a9012f76ba8d9189ae56a1f8bb7c87c07a1f3a - Patch | |
| References | () https://git.kernel.org/stable/c/3ff85ae79e1a74baeb916b78a63d821f6d19a994 - Patch | |
| References | () https://git.kernel.org/stable/c/669349b4612c26b3d7aacfa99d7174681bd19223 - Patch | |
| References | () https://git.kernel.org/stable/c/76f2ebaf79a9ae6d0737b87f045fe769e425d78f - Patch | |
| References | () https://git.kernel.org/stable/c/99dbab7b5a12d8f58d5b0aa2f7a1fe656a70f4b2 - Patch | |
| References | () https://git.kernel.org/stable/c/a9e777f856cd2f1efc106afc7bf21aef868509d5 - Patch | |
| First Time |
Linux linux Kernel
Linux |
|
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 7.8 |
01 Jun 2026, 17:17
| Type | Values Removed | Values Added |
|---|---|---|
| References |
|
27 May 2026, 11:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-05-27 11:16
Updated : 2026-06-26 19:08
NVD link : CVE-2026-45839
Mitre link : CVE-2026-45839
CVE.ORG link : CVE-2026-45839
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-129
Improper Validation of Array Index