CVE-2026-114117

Vyper 0.3.8 through 0.5.0b1 contains an optimizer miscompilation in which (msg.value | K) or (len(msg.data) | K), where K is any nonzero integer literal, is compiled to the constant 1 when used as a ternary expression branch under -O gas (the default) or -O codesize. Affected contracts use the wrong value in storage writes, arithmetic, indexes, return values, or events without warning or revert, which can record deposits incorrectly and lock funds.

CVSS 4.0

8.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS

0.3% chance of exploitation in the next 30 days; higher than 21% of CVEs (scores of 2026-10-25)

CWE

CWE-682

Published

2026-10-21

Modified

2026-10-22

Record from

the NVD, synced 2026-10-23

References

• https://github.com/vyperlang/vyper/security/advisories/GHSA-6j9c-gvcw-74fj
• https://www.vulncheck.com/advisories/vyper-0.3.8-through-0.5-0b1-optimizer-miscompilation-of-msg-value-k-in-ternary-branches
• https://github.com/vyperlang/vyper/security/advisories/GHSA-6j9c-gvcw-74fj

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