CVE-2026-54639CWE-1321

Style Dictionary - Prototype Pollution in convertTokenData utility function

High · published June 24, 2026

CVSS v3.1
8.8
EPSS
0%
Percentile
28.2
In the wild
Unconfirmed
What it is

Style Dictionary, a build system for creating cross-platform styles, has a prototype pollution vulnerability starting in version 4.3.0 and prior to version 5.4.4. Impact users have: direct usage of `convertTokenData(tokens, { output: 'object' });`; indirect usage, via using Expand API; and/or indirect usage via SD's transform lifecycle. Impact is high for this when style-dictionary is used as an integration in a NodeJS server application. Impact is moderate for when style-dictionary is used as an integration in a Web application. Impact is low for most common cases where the user of style-dictionary also maintains the tokens, and access is limited via read/write access to the repository/workflows where it is used. A patch has been published in version `5.4.4`. The only known workaround is to sanitize token data first. Whether using DTCG format or old Style Dictionary format, check the token data object recursively for any object keys that include `__proto__`.

The record
Technical detail
CVSS v3.1
8.8 · HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00357 · 28.2th percentile
Weakness
CWE-1321 · Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Published
2026-06-24T00:17Z
EPSS history
Timeline
  • 24 JUN 00:17Z
    Style Dictionary - Prototype Pollution in convertTokenData utility function
    cvelistv5