In the Linux kernel, the following vulnerability has been resolved:
bpf: zero extend the result of an arena 32-bit cmpxchg
bpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from
BPF_STX | BPF_ATOMIC to BPF_STX | BPF_PROBE_ATOMIC, and it runs before
bpf_opt_subreg_zext_lo32_rnd_hi32().
That pass emits an explicit zero extension for a 32-bit cmpxchg even
when bpf_jit_needs_zext() is false. This is done because on some
architectures 32-bit cmpxchg requires explicit zero extension for the
dst register. E.g. on x86-64 'lock cmpxchg' does not change the %eax
if comparison is successful, while BPF semantics declare that each
operation on a 32-bit register zero extends it's upper half.
is_cmpxchg_insn() matches BPF_MODE == BPF_ATOMIC only, so an arena
cmpxchg misses said zero extension adjustment. This patch adjusts
is_cmpxchg_insn() to match BPF_PROBE_ATOMIC alongside BPF_ATOMIC.
References
Configurations
Configuration 1 (hide)
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History
21 Oct 2026, 13:21
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| References |
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15 Oct 2026, 11:18
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| References |
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06 Oct 2026, 12:50
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| First Time |
Linux
Linux linux Kernel |
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| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.3:rc1:*:*:*:*:*:* |
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| References | () https://git.kernel.org/stable/c/1c1b476d43a8b6c9bc04600369dd8cc39950d98e - Patch | |
| References | () https://git.kernel.org/stable/c/4814ed6406f3493bd554ad046da5f7fc04833571 - Patch | |
| CVSS |
v2 : v3 : |
v2 : unknown
v3 : 5.5 |
| CWE | CWE-681 |
25 Sep 2026, 11:17
| Type | Values Removed | Values Added |
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| New CVE |
Information
Published : 2026-09-25 11:17
Updated : 2026-10-21 13:21
NVD link : CVE-2026-98049
Mitre link : CVE-2026-98049
CVE.ORG link : CVE-2026-98049
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-681
Incorrect Conversion between Numeric Types