CVE-2025-27104: vyper is a Pythonic Smart Contract Language for the EVM

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HIGH 7.5REMOTEUPGRADE

CVE-2025-27104 is a high-severity flaw (CVSS 7.5) affecting vyper. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

vyper is a Pythonic Smart Contract Language for the EVM. Multiple evaluation of a single expression is possible in the iterator target of a for loop. While the iterator expression cannot produce multiple writes, it can consume side effects produced in the loop body (e.g. read a storage variable updated in the loop body) and thus lead to unexpected program behavior. Specifically, reads in iterators which contain an ifexp (e.g. `for s: uint256 in (

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 61%)
CISA exploited list	No
Weakness	CWE-662
Published	2025-02-21
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: vyperlang

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-02-21 22:15 UTCPublished CVE record published
2026-06-17 09:03 UTCUpdated Record last modified

vyperlang vyper UPGRADE

Affected: < 0.4.1

Fixed in: 0.4.1

Safe to downgrade to: no unaffected older release

1. Check installed version

pip show vyper

2. UPGRADE to 0.4.1

pip install --upgrade "vyper>=0.4.1"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-27104?

vyper: upgrade to 0.4.1. Exact commands for each OS are on this page.

Is CVE-2025-27104 being exploited?

CVE-2025-27104 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-27104 affect?

CVE-2025-27104 affects vyper. Severity is high (CVSS 7.5). vyper is a Pythonic Smart Contract Language for the EVM. Multiple evaluation of a single expression is possible in the iterator target of a for loop. While the iterator expression cannot produce multiple writes, it can consume side effects

How urgent is CVE-2025-27104?

Priority 46/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-27105 CRITICAL 9.1 UPGRADE vyper is a Pythonic Smart Contract Language for the EVM
CVE-2025-26622 HIGH 7.5 UPGRADE vyper is a Pythonic Smart Contract Language for the EVM
CVE-2025-21607 HIGH 7.5 UPGRADE Vyper is a Pythonic Smart Contract Language for the EVM
CVE-2024-26149 LOW 3.7 UPGRADE Vyper is a pythonic Smart Contract Language for the ethereum virtual machine
CVE-2024-24567 MEDIUM 4.8 UPGRADE Vyper is a pythonic Smart Contract Language for the ethereum virtual machine

References

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