GHSA-ppx5-q359-pvwj
MEDIUMvyper's range(start, start + N) reverts for negative numbers
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
vyperReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
When looping over a range of the form range(start, start + N), if start is negative, the execution will always revert.
Details
This issue is caused by an incorrect assertion inserted by the code generation of the range (stmt.parse_For_range()):
This assertion was introduced in https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868 to fix https://github.com/advisories/GHSA-6r8q-pfpv-7cgj. 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.
PoC
@external
def foo():
x:int256 = min_value(int256)
# revert when it should not since we have the following assertion that fails:
# [assert, [le, min_value(int256), max_value(int256) + 1 - 10]],
for i in range(x, x + 10):
pass
Patches
patched in v0.4.0, specifically, https://github.com/vyperlang/vyper/pull/3679 disallows this form of range().
Impact
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | vyper | ≥ 0.3.8&&< 0.4.0 | 0.4.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for vyper. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update vyper to 0.4.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-ppx5-q359-pvwj is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-ppx5-q359-pvwj is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-ppx5-q359-pvwj. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-ppx5-q359-pvwj in your dependencies?
O3 detects GHSA-ppx5-q359-pvwj across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.