Answer in brief
CVE-2026-123566 records a High severity (CVSS 8.7) vulnerability in Devalue before 5.9.3 CPU Amplification Denial of Service via uneval. The current sources do not mark it as known exploited. The current feed maps sveltejs/devalue (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 8.7. 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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| sveltejs/devaluegeneric | >=0 <5.9.3 | 5.9.3 |
Published upstream
Nov 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Nov 8, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Nov 8, 2026
Sveltejs devalue before 5.9.3 contains a denial of service vulnerability that allows attackers to cause CPU amplification by supplying sparse arrays to uneval. Attackers who influence sparse values passed to uneval can force synchronous work proportional to the declared array length, blocking the event loop.
Quoted source text, attributed separately from HOL analysis.