CVE-2025-47774: PYSEC-2026-2028 - Vyper's `slice()` may elide side-effects when output length is 0

CVE-2025-47774 · Severity: medium · CVSS 4 · Published 2026-07-07

Vyper's `slice()` may elide side-effects when output length is 0

Technologies: vyper (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2025-47774 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-47774 being exploited in the wild.
How severe is CVE-2025-47774?
Medium severity, with a CVSS score of 4, published 7 July 2026.
Which products and versions are affected?
vyper (PyPI) ECOSYSTEM:introduced=0,last_affected=0.4.2rc1.
Is there a fix for CVE-2025-47774?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
Am I affected by CVE-2025-47774?
Check whether you run vyper (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Affected products

  • vyper (PyPI) ECOSYSTEM:introduced=0,last_affected=0.4.2rc1

Identifiers

  • CVE-2025-47774
  • GHSA-3vcg-j39x-cwfm
  • PYSEC-2026-2028

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.