Answer in brief
CVE-2021-48012 records a High severity (CVSS 8.8) vulnerability in fast-toml through 0.5.4 Prototype Pollution via __proto__ Keys in Parsed TOML. The current sources do not mark it as known exploited. The current feed maps Gin-Quin/fast-toml (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 8.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Gin-Quin/fast-toml (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Gin-Quin/fast-tomlgeneric | >=0 <=0.5.4 | Not reported |
Published upstream
Oct 12, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 12, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 12, 2026
fast-toml through 0.5.4 contains a prototype pollution vulnerability that allows attackers to modify Object.prototype by supplying TOML containing __proto__, constructor or prototype key segments. Attackers can pass [__proto__] or [constructor.prototype] table headers or __proto__.x dotted keys to parse() to pollute all objects, causing denial of service or authorization bypass.
Quoted source text, attributed separately from HOL analysis.