Vulnerability record · CVE-2026-15076 · published 14 July 2026
CVE-2026-15076: Eclipse vert.x origin validation error vulnerability
Eclipse · Vert.X
In versions up to and including 4.5.29 (4.x branch) and 5.1.4 (5.x branch), the WebClientSession component of Eclipse Vert.x Web Client does not validate that the Domain attribute of a Set-Cookie response header matches the originating server's domain, in violation of RFC 6265 section 5.3. An attacker who controls any server that the victim application contacts can inject a cookie scoped to an arbitrary third-party domain; because the session store performs no cross-domain ownership check, it stores and later transmits that cookie to the targeted domain. When the victim application subsequently sends a request to the targeted domain using the same WebClientSession, it presents the attacker-injected cookie, causing the receiving service to process the request under the attacker's account. Sensitive data included in the victim application's requests, such as payment amounts, card details, or other API payloads, may then be accessible to the attacker through their own account on that service.
Description
In versions up to and including 4.5.29 (4.x branch) and 5.1.4 (5.x branch), the WebClientSession component of Eclipse Vert.x Web Client does not validate that the Domain attribute of a Set-Cookie response header matches the originating server's domain, in violation of RFC 6265 section 5.3. An attacker who controls any server that the victim application contacts can inject a cookie scoped to an arbitrary third-party domain; because the session store performs no cross-domain ownership check, it stores and later transmits that cookie to the targeted domain. When the victim application subsequently sends a request to the targeted domain using the same WebClientSession, it presents the attacker-injected cookie, causing the receiving service to process the request under the attacker's account. Sensitive data included in the victim application's requests, such as payment amounts, card details, or other API payloads, may then be accessible to the attacker through their own account on that service.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://gitlab.eclipse.org/security/cve-assignment/-/work_items/162 | Issue Tracking |
Track CVE-2026-15076 inside VULONE
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2026-15076), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
