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How the mentioned CVE works:
This vulnerability targets the Vert.x Web static handler’s caching mechanism. It stems from an improper implementation of rule C in RFC3986 section 5.2.4 for URI normalization. An attacker can craft a malicious request URI containing a URL-encoded forward slash (%2F) followed by a directory traversal sequence (..). For example, requesting `/foo/bar%2F..%2Findex.html` instead of /foo/index.html. The static handler’s cache logic fails to correctly interpret the encoded slash during path resolution. This causes the handler to compute an incorrect cache key for the requested resource. Consequently, the cache stores a key for a non-existent path (foo/bar/index.html). All subsequent legitimate requests for the original file (/foo/index.html) are served from this corrupted cache entry. The final result is a false HTTP 404 (Not Found) response, denying access to the static file.
DailyCVE Form:
Platform: Vert.x Web
Version: Core component
Vulnerability: Cache Poisoning
Severity: Moderate
date: 2026-01-15
Prediction: 2026-01-29
What Undercode Say:
Analytics:
`curl -v “https://example.com/foo/index.html”`
`curl -v “https://example.com/foo/bar%2F..%2Findex.html”`
How Exploit:
Craft URI with `%2F..%2F`.
Protection from this CVE
`StaticHandler.create().setCachingEnabled(false);`
Impact:
Denial of Service (404).
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Sources:
Reported By: github.com
Extra Source Hub:
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