Vulnerability Details CVE-2026-43070
In the Linux kernel, the following vulnerability has been resolved:
bpf: Reset register ID for BPF_END value tracking
When a register undergoes a BPF_END (byte swap) operation, its scalar
value is mutated in-place. If this register previously shared a scalar ID
with another register (e.g., after an `r1 = r0` assignment), this tie must
be broken.
Currently, the verifier misses resetting `dst_reg->id` to 0 for BPF_END.
Consequently, if a conditional jump checks the swapped register, the
verifier incorrectly propagates the learned bounds to the linked register,
leading to false confidence in the linked register's value and potentially
allowing out-of-bounds memory accesses.
Fix this by explicitly resetting `dst_reg->id` to 0 in the BPF_END case
to break the scalar tie, similar to how BPF_NEG handles it via
`__mark_reg_known`.
Exploit prediction scoring system (EPSS) score
EPSS Score 0.0
EPSS Ranking 3.3%
CVSS Severity
CVSS v3 Score 7.8
References
Products affected by CVE-2026-43070
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cpe:2.3:o:linux:linux_kernel:6.18.17
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cpe:2.3:o:linux:linux_kernel:6.18.18
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cpe:2.3:o:linux:linux_kernel:6.18.19
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cpe:2.3:o:linux:linux_kernel:6.18.20
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cpe:2.3:o:linux:linux_kernel:6.19.10
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cpe:2.3:o:linux:linux_kernel:6.19.7
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cpe:2.3:o:linux:linux_kernel:6.19.8
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cpe:2.3:o:linux:linux_kernel:6.19.9
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cpe:2.3:o:linux:linux_kernel:7.0