CVE-2026-54639: Style Dictionary - Prototype Pollution
Affects style-dictionarySource GCVE Database
Not known to be exploited · CVSS 8.8 High : upgrade to 5.4.4 soon.
Data as of 28 Oct 2026, 05:11 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 29% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 5.4.4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 28 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade style-dictionary to 5.4.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| npmstyle-dictionary | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available in Style Dictionary version 5.4.4. Users should upgrade to this version or later to remediate the vulnerability. As a workaround, sanitize token data before processing by recursively checking for keys containing '__proto__' and rejecting such tokens. Additionally, set the expand configuration option to false to prevent indirect exploitation via the Expand API. Example code for detection is provided in the advisory.
Description
Style Dictionary versions from 4.3.0 up to but not including 5.4.4 contain a prototype pollution vulnerability in the convertTokenData utility function. This vulnerability allows a malicious user to inject tokens with keys like '{__proto__.foo}', which pollutes the global Object.prototype. The vulnerability affects direct usage of convertTokenData as well as indirect usage via the Expand API or the transform lifecycle. The impact is highest when Style Dictionary is integrated into NodeJS server applications, moderate for web applications, and low when token data is tightly controlled. A patch is available in version 5.4.4. Workarounds include sanitizing token data to reject keys containing '__proto__' and disabling the expand feature.
References
- github.com/style-dictionary/style-dictionary/security/advisories/GHSA-vj5c-m527-mpff (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-54639 (opens in a new tab)
- github.com/style-dictionary/style-dictionary/pull/1702 (opens in a new tab)
- github.com/style-dictionary/style-dictionary/commit/209085d9782cfc0783c4d983f3f1bb2c515954ec (opens in a new tab)
- github.com/style-dictionary/style-dictionary/commit/23b5e8dda143441f0d6b8e2b4222e2da98058bc5 (opens in a new tab)
- github.com/style-dictionary/style-dictionary (opens in a new tab)
- github.com/style-dictionary/style-dictionary/releases/tag/v5.4.4 (opens in a new tab)