Use of Cache Containing Sensitive Information Affecting io.vertx:vertx-web-client package, versions [4.0.0.Beta1,4.5.36)[5.0.0.CR1,5.2.3)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-JAVA-IOVERTX-22190589
- published4 Nov 2026
- disclosed3 Nov 2026
- creditdpfkdlemtp
Introduced: 3 Nov 2026
NewCVE-2026-118489 (opens in a new tab)How to fix?
Upgrade io.vertx:vertx-web-client to version 4.5.36, 5.2.3 or higher.
Overview
Affected versions of this package are vulnerable to Use of Cache Containing Sensitive Information in the CacheInterceptor class, whose shared cache key carries no per-user marker and which decides to store a response in the client level shared tier from Cache-Control and Expires alone. An attacker can read another user's response body by requesting the same URL through a CachingWebClient that serves multiple principals, since a response to a request carrying an Authorization header is stored in the shared tier even though max-age alone does not make it shareable, after which a session private miss falls back to that tier and an anonymous request receives the stored body in place of the origin's 401. Where the stored response carries Set-Cookie, the cookie is replayed verbatim to later callers, handing one user's session identifier to another and enabling session fixation or hijacking. Both cases require a single CachingWebClient shared across user principals, which is the documented pattern of a per-user WebClientSession layered over a shared caching client, together with an origin that marks the response cacheable without private or no-store.