Answer in brief
CVE-2026-44573 records a High severity (CVSS 7.5) vulnerability in Next.js: Middleware / Proxy bypass in Pages Router applications using i18n. The current sources do not mark it as known exploited. The current feed maps vercel/next.js (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 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 vercel/next.js (generic). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:a:vercel:next.js:*:*:*:*:*:node.js:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| vercel/next.jsgeneric | >= 12.2.0, < 15.5.16 || >= 16.0.0, < 16.2.5 | Not reported |
Published upstream
May 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 13, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jul 3, 2026
Next.js is a React framework for building full-stack web applications. From 12.2.0 to before 15.5.16 and 16.2.5, Applications using the Pages Router with i18n configured and middleware/proxy-based authorization can allow unauthorized access to protected page data through locale-less /_next/data/<buildId>/<page>.json requests. In affected configurations, middleware does not run for the unprefixed data route, allowing an attacker to retrieve SSR JSON for protected pages without passing the intended authorization checks. This vulnerability is fixed in 15.5.16 and 16.2.5.
Quoted source text, attributed separately from HOL analysis.