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TI-2025-19975 Aliases CVE-2025-27105GHSA-4w26-8p97-f4jp

AugAssign evaluation order causing OOB write within the object in Vyper

Priority LOW 19CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
Low · Low · Low
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.

Summary

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 to upgrade. There are no known workarounds for this vulnerability.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.0057 47th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed vyper (vyperlang): 0.4.1vyper (PyPI): 0.4.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
vyperlangvyperbefore 0.4.10.4.1Patch availableCNA
—vyper (PyPI)before 0.4.10.4.1Patch availableGHSA-4w26-8p97-f4jp
  • vyper Vendorvyperlang Affected before 0.4.1 Fixed in 0.4.1 Patch available CNA
  • vyper (PyPI) Vendor— Affected before 0.4.1 Fixed in 0.4.1 Patch available GHSA-4w26-8p97-f4jp

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:python:*:*before 0.4.1Vulnerablevyperlang
  • cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:python:*:* Versions before 0.4.1 Vulnerable ·vyperlang

Remediation

  • Fix · CNA vyper (vyperlang) Fixed in 0.4.1
  • Fix · GHSA-4w26-8p97-f4jp vyper (PyPI) Fixed in 0.4.1 Advisory →

Vendor assessments

Red Hat

Red Hat's page for this CVE →

Not affected: 1 product
  • Red Hat

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-27105
  2. 2026-10-03 Alias added: GHSA-4w26-8p97-f4jp

References

Exploit 1

Advisory 1

Other 2

  • TI-2024-16182 Vyper bounds check on built-in `slice()` function can be overflowed CVSS 3.1CRITICAL 9.8
  • TI-2024-14992 concat built-in can corrupt memory in vyper CVSS 3.1CRITICAL 9.8
  • TI-2024-16184 Vyper array negative index vulnerability CVSS 3.1CRITICAL 9.8
  • TI-2022-08657 Integer bounds error in Vyper CVSS 3.1CRITICAL 9.8
  • TI-2022-11796 Multiple evaluation of contract address in call in vyper CVSS 3.1HIGH 8.2
  • TI-2024-21531 vyper performs double eval of the argument of sqrt CVSS 3.1MEDIUM 5.3
See all 37 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences