CVE-2024-32481

vyper's range(start, start + N) reverts for negative numbers

MEDIUM
5.3
CVSS Score
Published: April 25, 2024 at 05:00 PM UTC
Updated: June 17, 2026 at 07:29 AM UTC
1 product affected across 1 vendorVyper

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.8%
SSVC
PoC

Description

Vyper is a pythonic Smart Contract Language for the Ethereum virtual machine. Starting in version 0.3.8 and prior to version 0.4.0b1, when looping over a `range` of the form `range(start, start + N)`, if `start` is negative, the execution will always revert. This issue is caused by an incorrect assertion inserted by the code generation of the range `stmt.parse_For_range()`. The issue arises when `start` is signed, instead of using `sle`, `le` is used and `start` is interpreted as an unsigned integer for the comparison. If it is a negative number, its 255th bit is set to `1` and is hence interpreted as a very large unsigned integer making the assertion always fail. Any contract having a `range(start, start + N)` where `start` is a signed integer with the possibility for `start` to be negative is affected. If a call goes through the loop while supplying a negative `start` the execution will revert. Version 0.4.0b1 fixes the issue.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.4.0b10.3.8 ≤ v ≤ 0.3.100.3.8 ≤ v ≤ 0.4.0b10.3.80.4.0
Affected range stops below 0.4.0b1, so it looks safe — our inference, not a vendor statement

SSVC — Action Prioritization

SSVCPoCAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-681

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