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__.
CVE-2026-54639
“—” beside the score: it is equal to the CVSS score beside it.
Score 8.8 from GitHub Security Advisory (severity: HIGH) published 2026-07-28. A secondary CVSS source baseline 8.8; sources differ by 0.0.
Also known asEUVD-2026-38640 (ENISA EUVD) · GHSA-vj5c-m527-mpff (GitHub Security Advisories)Source: ENISA EUVD
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 8.8
- EG Score
- 8.8HIGHmedium confidence
- EG Risk
- 40EG Risk 40/100
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
How it’s computed (value × EchelonGraph’s weight)Severity88% × 45%Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.4% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability0% × 15%CISA's SSVC Automatable value: no (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.Action: A fix is available. Apply it within your standard update timelines. - EPSS PROB
- 0.4%
- EPSS %ILE
- 29th
- KEV
- Not listed
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.
- EG Severity
- 8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.4% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- SSVC Track at medium mission impactTrack at low or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
Published
June 24, 2026
Last Modified
October 25, 2026
Advisory Details (4)
Auto-updated Jun 24, 2026Style Dictionary - Prototype Pollution in convertTokenData utility function · Advisory · style-dictionary/style-dictionary · GitHub
https://github.com/style-dictionary/style-dictionary/security/advisories/GHSA-vj5c-m527-mpfffix: prototype pollution in convertTokenData utility
Patch available: style-dictionary/style-dictionary v5.4.4 (PR #1702 merged 2026-06-08)
https://github.com/style-dictionary/style-dictionary/pull/1702commit 23b5e8dda143 (style-dictionary/style-dictionary)
Patch available: style-dictionary/style-dictionary v5.4.4 (contains commit 23b5e8dda143)
https://github.com/style-dictionary/style-dictionary/commit/23b5e8dda143441f0d6b8e2b4222e2da98058bc5commit 209085d9782c (style-dictionary/style-dictionary)
Patch available: style-dictionary/style-dictionary v4.3.0 (contains commit 209085d9782c)
https://github.com/style-dictionary/style-dictionary/commit/209085d9782cfc0783c4d983f3f1bb2c515954ecVendor Advisories for CVE-2026-54639(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(1)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| npm | style-dictionary @ 5.4.4 (fixes >= 4.3.0, < 5.4.4) | — | ghsa |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
npm(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| style-dictionary | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 11× in last 7d / 43× in last 30d)
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 100 of 174 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 74 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
- 2026-11-02 03:49 UTCEG score recompute
- 2026-11-02 03:49 UTCGHSA enrichmentGHSA-vj5c-m527-mpff · GitHub severity HIGH · GitHub CVSS 8.8
- 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-11-01 07:44 UTCGHSA enrichmentGHSA-vj5c-m527-mpff · GitHub severity HIGH · GitHub CVSS 8.8
- 2026-11-01 07:44 UTCEG score recompute
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.4% · 29th percentile
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- 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-10-25 23:32 UTCEG score recompute
- 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-10-25 14:19 UTCEG score recompute
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.4% · 28th percentile
- 2026-10-24 08:18 UTCEG score recompute
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.4% · 28th percentile
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- 2026-10-18 03:30 UTCEG score recompute
- 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.4% · 27th percentile
- 2026-10-17 04:00 UTCEG score recompute
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- 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.4% · 27th percentile
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- 2026-10-14 06:54 UTCOSV refresh
- 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.4% · 27th percentile
- 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.4% · 27th percentile
- 2026-10-12 15:56 UTCEG score recompute
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- 2026-10-11 14:17 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.4% · 27th percentile
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- 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.4% · 27th percentile
- 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.4% · 26th percentile
- 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.4% · 26th percentile
- 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.4% · 26th percentile
- 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.4% · 26th percentile
- 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.4% · 26th percentile
- 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-09-23 11:56 UTCEG score recompute
- 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.4% · 29th percentile
- 2026-09-18 10:19 UTCEG score recompute
- 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.4% · 29th percentile
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- 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.4% · 29th percentile
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- 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.4% · 28th percentile
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- 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.4% · 28th percentile
- 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.4% · 28th percentile
- 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.4% · 28th percentile
- 2026-08-30 20:24 UTCEG score recompute
- 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.4% · 28th percentile
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- 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.4% · 28th percentile
- 2026-08-24 22:05 UTCEG score recompute
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- 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
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- 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
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- 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
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- 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
- 2026-08-17 03:06 UTCEG score recompute
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- 2026-08-14 00:23 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-54639?
When was the CVE record for CVE-2026-54639 published?
Is CVE-2026-54639 actively exploited?
What is the CVSS score of CVE-2026-54639?
How do I remediate CVE-2026-54639?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-54639
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