CVE-2026-114114 PUBLISHED

Vyper through 0.5.0b1 Literal Value Substitution via Multi-byte Characters

Assigner: VulnCheck
Reserved: 20.10.2026 Published: 21.10.2026 Updated: 21.10.2026

Vyper 0.1.0b1 before 0.1.0b12, 0.1.0b14, and 0.4.1 through 0.5.0b1 mix character-based line offsets with Python's UTF-8 byte col_offset values in vyper/ast/parse.py, so multi-byte characters shift the source slices used to reconstruct later numeric literals. An attacker contributing source with non-ASCII identifiers that NFKC-normalize to ASCII, or an invisible byte-order mark, can silently substitute addresses, integers or other constants in compiled code.

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CVSS Score: 6

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	Present	Availability	None	Availability	None
Privileges Required	None
User Interaction	Passive

CVSS 4.0

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
CVSS Score: 5.3

Attack Vector	Network	Scope	Unchanged
Attack Complexity	High	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	High
User Interaction	Required	Availability Impact	None

CVSS 3.1

Product Status

Vendor	vyperlang
Product	vyper
Versions	Default: unaffected affected from 0.1.0b1 to 0.1.0b12 (excl.) Version 0.1.0b12 is unaffected

Vendor	vyperlang
Product	vyper
Versions	Default: unaffected affected from 0.1.0b14 to 0.1.0b15 (excl.) Version 0.1.0b15 is unaffected

Vendor	vyperlang
Product	vyper
Versions	Default: unaffected affected from 0.4.1 to 0.5.0b1 (incl.)

CVE-2026-114114 PUBLISHED

Vyper through 0.5.0b1 Literal Value Substitution via Multi-byte Characters

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Credits

References

Problem Types