CVE-2026-118489

CachingWebClient shares user-specific HTTP responses across users via the shared cache tier

Published Nov 3, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Eclipse
Eclipse vert.x
Eclipse Foundation
Eclipse Foundation vert.x
Vendors & Products Eclipse
Eclipse vert.x
Eclipse Foundation
Eclipse Foundation vert.x
Type Values Removed Values Added
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.
Title CachingWebClient shares user-specific HTTP responses across users via the shared cache tier
Weaknesses CWE-200
CWE-524
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
eclipse
Published
Updated
Nov 3, 2026, 6:09 PM
Reserved
Oct 28, 2026, 11:32 AM
Status
Deferred
Published
Nov 3, 2026, 3:17 PM
Modified
Nov 3, 2026, 7:17 PM
Severity
Important
Public date
Nov 3, 2026, 2:55 PM