Answer in brief
CVE-2026-50029 records a Medium severity (CVSS 5.3) vulnerability in js-toml has silent type confusion via falsy-primitive duplicate-key bypass. The current sources do not mark it as known exploited. The current feed maps sunnyadn/js-toml (generic), js-toml (npm). 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 5.3. 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 sunnyadn/js-toml (generic), js-toml (npm). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| sunnyadn/js-tomlgeneric | <1.1.2 | 1.1.2 |
| js-tomlnpm | <=1.1.1 | 1.1.2 |
Published upstream
Aug 14, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 18, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 26, 2026
js-toml is a TOML parser for JavaScript, Prior to version 1.1.2, the interpreter checks whether a key already exists in a parser-built container with `if (object[key])` instead of `if (key in object)`. When the prior value is a falsy primitive — `false`, `0`, `0n`, `0.0`, `-0`, or `""` — the duplicate-key branch is skipped and the value is silently overwritten by a later sub-table, dotted-key sub-table, or array-of-tables sharing the same name. Per the TOML 1.0.0 spec ("Defining a key multiple times is invalid"; "You cannot define any key or table more than once"), this should be a parse error. The result is structural type confusion of attacker-named keys in the value returned by `load()`. A boolean-typed `false` (or numeric `0`) becomes a truthy object. Host applications that gate behavior on `if (config.flag)`, `if (!user.banned)`, `if (config.allowDelete)`, or `if (config.publicMode)` will silently take the truthy branch. This is distinct from GHSA-65fc-cr5f-v7r2 (the 1.0.2 prototype-pollution fix). `Object.prototype` is not polluted. The `Object.create(null)` mitigation from 1.0.2 is intact; the bug here is in the duplicate-key state machine, not in container construction. Version 1.1.2 patches the incorrect comparison.
Quoted source text, attributed separately from HOL analysis.