CVE-2026-118489

HIGHCVSS 7.5/10

Last modified

CVE-2026-118489 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. In Eclipse Vert.x versions [4.0.0,4.5.35] or [5.0.0,5.2.2], when one `CachingWebClient` is shared across users — the documented pattern of a per-user `WebClientSession` over a shared caching client — a response that is specific to one user but is cacheable and not marked `private`/`no-store` is stored in the client-level shared cache tier and served to other users requesting the same URL. A later user's session, or an anonymous caller through the same client, can receive an earlier user's response.

Description

In Eclipse Vert.x versions [4.0.0,4.5.35] or [5.0.0,5.2.2], when one `CachingWebClient` is shared across users — the documented pattern of a per-user `WebClientSession` over a shared caching client — a response that is specific to one user but is cacheable and not marked `private`/`no-store` is stored in the client-level shared cache tier and served to other users requesting the same URL. A later user's session, or an anonymous caller through the same client, can receive an earlier user's response. Depending on the response this discloses authenticated content or a session cookie, the latter enabling session fixation or hijacking.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
Eclipse FoundationEclipse Vert.x>= 4.0.0, <= 4.5.35; >= 5.0.0, <= 5.2.2

References

Timeline

Published
Last Modified
Status
Deferred

Frequently Asked Questions

What is CVE-2026-118489?
In Eclipse Vert.x versions [4.0.0,4.5.35] or [5.0.0,5.2.2], when one `CachingWebClient` is shared across users — the documented pattern of a per-user `WebClientSession` over a shared caching client — a response that is specific to one user but is cacheable and not marked `private`/`no-store` is stored in the client-level shared cache tier and served to other users requesting the same URL. A later user's session, or an anonymous caller through the same client, can receive an earlier user's response. Depending on the response this discloses authenticated content or a session cookie, the latter enabling session fixation or hijacking.
How severe is CVE-2026-118489?
CVE-2026-118489 has a CVSS score of 7.5/10 (HIGH severity).
How do I fix CVE-2026-118489?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST