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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements Present

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact None

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity High

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact High

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
vyperlang vyper unaffected
Version Status Constraints
0.3.8 affected ≤ 0.5.0b1

No data.

No data.

No data.

Project Subscriptions

Vendors Products
Vyperlang Subscribe
Vyper Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

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

Wed, 21 Oct 2026 00:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Vyper 0.3.8 through 0.5.0b1 Optimizer Miscompilation of msg.value | K in Ternary Branches
First Time appeared Vyperlang
Vyperlang vyper
Weaknesses CWE-682
CPEs cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:*:*:*
Vendors & Products Vyperlang
Vyperlang vyper
References
Metrics cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N'}

cvssV4_0

{'score': 8.2, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-10-21T00:37:14.741Z

Reserved: 2026-10-20T21:48:58.503Z

Link: CVE-2026-114117

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-21T01:17:38.070

Modified: 2026-10-21T01:17:38.070

Link: CVE-2026-114117

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses