Answer in brief
CVE-2026-42570 records a High severity (CVSS 7.5) vulnerability in Svelte devalue: DoS via sparse array deserialization. The current sources do not mark it as known exploited. The current feed maps sveltejs/devalue (generic), devalue (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 7.5. 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 sveltejs/devalue (generic), devalue (npm). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:svelte:devalue:*:*:*:*:*:node.js:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| sveltejs/devaluegeneric | >= 5.6.3, < 5.8.1 | Not reported |
| devaluenpm | >=5.6.3,<=5.8.0 | 5.8.1 |
Published upstream
Jun 9, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 11, 2026
Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. From version 5.6.3 to before version 5.8.1, devalue.parse could, due to quirks in some JavaScript engines, be convinced to allocate much more memory than was needed when deserializing sparse arrays, leading to excessive memory consumption. This issue has been patched in version 5.8.1.
Quoted source text, attributed separately from HOL analysis.