Vert.x 4.5.29/5.1.4: Header Leak via CrossOrigin Redirect
CVE-2026-15075 Published on July 14, 2026
In Eclipse Vert.x versions up to and including 4.5.29 (4.x branch) and 5.1.4 (5.x branch), DefaultRedirectHandler (vertx-core) propagates all request headers as-is across cross-origin HTTP 30x redirects. Only Content-Length is stripped; no origin comparison (scheme, host, port) is performed before copying headers to the redirect target. As a result, credential headers, including Authorization, Cookie, Proxy-Authorization, and arbitrary custom headers such as X-API-Token, are forwarded to the redirect destination without the caller's knowledge. An attacker who can cause a Vert.x HttpClient to issue a request that is redirected to an attacker-controlled host (for example, by supplying a URL to a webhook dispatcher, image proxy, or microservice URL fetcher) can capture bearer tokens, basic-auth credentials, session cookies, and API keys attached to the original request.
Weakness Types
What is an Information Disclosure Vulnerability?
The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.
CVE-2026-15075 has been classified to as an Information Disclosure vulnerability or weakness.
Origin Validation Error
The software does not properly verify that the source of data or communication is valid.
Products Associated with CVE-2026-15075
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Affected Versions
Eclipse Foundation Eclipse Vert.x:- Version 4.0.0, <= 4.5.29 is affected.
- Version 5.0.0, <= 5.1.4 is affected.