Prototype Pollution Vulnerability in Deno Standard Library by Deno
CVE-2025-55195

7.3HIGH

Key Information:

Vendor

Denoland

Status
Std
Vendor
CVE Published:
14 August 2025

What is CVE-2025-55195?

The Deno Standard Library's @std/toml module, before version 1.0.9, is susceptible to a prototype pollution vulnerability. This occurs when untrusted TOML data is parsed, causing the merging of an untrusted object with an empty object that retains the prototype chain. This flaw can enable attackers to manipulate the prototype chain in both Node.js and Browser environments, potentially leading to severe security issues. The issue has been addressed in the patched release version 1.0.9.

Affected Version(s)

std < 1.0.9

References

https://github.com/denoland/std/security/advisories/GHSA-...
x_refsource_CONFIRM
https://github.com/denoland/std/commit/540662cfd6d71e969a...
x_refsource_MISC
https://github.com/denoland/std/releases/tag/release-2025...
x_refsource_MISC

CVSS V3.1

Score:
7.3
Severity:
HIGH
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.