CVE-2026-15075
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn 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.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceIn Eclipse Vert.x, the DefaultRedirectHandler copies all request headers (Authorization, Cookie, X-API-Token, etc.) to redirect target URLs without validating whether the redirect destination has a different origin (scheme/host/port). Only Content-Length is stripped. An attacker who can trigger a redirect to an attacker-controlled host can capture sensitive credentials from the original request.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 4.5.29>= 5.0.0, <= 5.1.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Vert.x versionInspect project dependencies (Maven pom.xml, Gradle build.gradle, or JAR manifest) for vertx-core or vertx package version. Run 'mvn dependency:tree' or 'gradle dependencies' to list Vert.x artifacts and their versions.Affected if The installed Vert.x version is 4.5.29 or lower, OR between 5.0.0 and 5.1.4 inclusive.
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Confirm DefaultRedirectHandler usageSearch source code for 'setRedirectHandler' or 'DefaultRedirectHandler' configuration on HttpClient or WebClient instances. Check HttpClientOptions for redirect handler settings.Affected if The application configures or defaults to using DefaultRedirectHandler for HTTP client redirects.
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Verify redirect functionality is enabledReview HttpClientOptions configuration for 'setMaxRedirects' (non-zero) or 'setFollowRedirects' (true). Search code for any manual redirect handling logic.Affected if The HTTP client is configured to follow redirects (max redirects > 0).
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Check redirect destination logicAnalyze application code to determine if redirects can target external/untrusted hosts. Review any redirect URL construction logic that accepts user input or fetches URLs from external sources.Affected if Redirects can go to arbitrary URLs, especially different origins (scheme/host/port combinations).
You are affected if your Vert.x version falls within 4.5.29 or lower, or 5.0.0 through 5.1.4, AND your application uses DefaultRedirectHandler to follow redirects to potentially different origins.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpgrade to Vert.x 4.5.30+ or 5.1.5+ which implement origin validation before forwarding sensitive headers, or implement a custom RedirectHandler that verifies the redirect target shares the same origin before propagating credential headers.
Vert.x 4.x: upgrade to 4.5.30 or later; Vert.x 5.x: upgrade to 5.1.5 or later (or latest stable in respective branch)
- 1. Identify all applications using Eclipse Vert.x vertx-core library with versions <= 4.5.29 or >= 5.0.0 through dependency management (e.g., Maven pom.xml, Gradle build.gradle)
- 2. Update the Vert.x dependency to version 4.5.30 or later for 4.x branch applications
- 3. Update the Vert.x dependency to version 5.1.5 or later for 5.x branch applications
- 4. Alternatively, upgrade to the latest stable release in your respective branch (4.x latest or 5.x latest) to include all security fixes
- 5. Rebuild and test the application to ensure redirect behavior works correctly with the new version
- 6. Verify that sensitive headers are no longer forwarded across cross-origin redirects by testing HTTP redirects to different hosts
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-15075 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-15075 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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