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.
https://github.com/vyperlang/vyper/security/advisories/GHSA-r3c7-7xwm-6vfw
Published: 2026-10-21
Updated: 2026-10-22
Base Score: 5.4
Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:C/A:N
Severity: Medium
Base Score: 5.3
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
Severity: Medium
Base Score: 6
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
Severity: Medium
EPSS: 0.00183