Medium severity · published Oct 21, 2026
CVE-2026-114114
Vyper through 0.5.0b1 Literal Value Substitution via Multi-byte Characters
5.3
CVSS
0.2%
EPSS
No
On KEV
Description
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:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
Attack vector
Network
Complexity
High
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
High
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 8% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
VY
vyper · vyperlang
0.1.0b1 before 0.1.0b12; 0.1.0b14 before 0.1.0b15; 0.4.1 through 0.5.0b1 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-114114
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-114114
github.com
https://github.com/vyperlang/vyper/security/advisories/GHSA-r3c7-7xwm-6vfw
www.vulncheck.com
https://www.vulncheck.com/advisories/vyper-through-0.5-0b1-literal-value-substitution-via-multi-byte-characters
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