CVE-2025-27105: vyper is a Pythonic Smart Contract Language for the EVM

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CRITICAL 9.1REMOTEUPGRADE

CVE-2025-27105 is a critical-severity flaw (CVSS 9.1) 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. Vyper handles AugAssign statements by first caching the target location to avoid double evaluation. However, in the case when target is an access to a DynArray and the rhs modifies the array, the cached target will evaluate first, and the bounds check will not be re-evaluated during the write portion of the statement. This issue has been addressed in version 0.4.1 and all users are advised

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 53%)
CISA exploited list	No
Weakness	CWE-787
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-2025-27105?

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

Is CVE-2025-27105 being exploited?

CVE-2025-27105 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-2025-27105 affect?

CVE-2025-27105 affects vyper. Severity is critical (CVSS 9.1). vyper is a Pythonic Smart Contract Language for the EVM. Vyper handles AugAssign statements by first caching the target location to avoid double evaluation. However, in the case when target is an access to a DynArray and the rhs modifies th

How urgent is CVE-2025-27105?

Priority 54/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-27104 HIGH 7.5 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

References

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