CVE-2026-15076
Eclipse Vert.x Improper Cookie Domain Validation Vulnerability
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.
INFO
Published Date :
July 14, 2026, 9:16 a.m.
Last Modified :
Oct. 24, 2026, 10:10 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | HIGH | e51fbebd-6053-4e49-959f-1b94eeb69a2c | ||||
| CVSS 4.0 | HIGH | [email protected] |
Solution
- Update Eclipse Vert.x Web Client.
- Validate cookie domain attributes.
- Implement cross-domain ownership checks.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-15076.
| URL | Resource |
|---|---|
| https://gitlab.eclipse.org/security/cve-assignment/-/work_items/162 | Issue Tracking |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-15076 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-15076
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-15076 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-15076 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Added Translation Title: Eclipse Vert.x de Eclipse Foundation, Description: En versiones hasta la 4.5.29 (inclusive) (rama 4.x) y la 5.1.4 (rama 5.x), el componente WebClientSession de Eclipse Vert.x Web Client no valida que el atributo Domain de una cabecera de respuesta Set-Cookie coincida con el dominio del servidor de origen, en violación de la sección 5.3 de RFC 6265. Un atacante que controla cualquier servidor con el que la aplicación víctima contacta puede inyectar una cookie con ámbito a un dominio de terceros arbitrario; debido a que el almacén de sesiones no realiza ninguna comprobación de propiedad entre dominios, almacena y posteriormente transmite esa cookie al dominio objetivo. Cuando la aplicación víctima posteriormente envía una solicitud al dominio objetivo utilizando la misma WebClientSession, presenta la cookie inyectada por el atacante, haciendo que el servicio receptor procese la solicitud bajo la cuenta del atacante. Datos sensibles incluidos en las solicitudes de la aplicación víctima, como importes de pago, detalles de tarjetas u otras cargas útiles de API, pueden entonces ser accesibles para el atacante a través de su propia cuenta en ese servicio. -
Initial Analysis by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N Added CPE Configuration OR *cpe:2.3:a:eclipse:vert.x:*:*:*:*:*:*:*:* versions from (including) 5.0.0 up to (including) 5.1.4 *cpe:2.3:a:eclipse:vert.x:*:*:*:*:*:*:*:* versions from (including) 4.0.0 up to (including) 4.5.29 Added Reference Type Eclipse Foundation: https://gitlab.eclipse.org/security/cve-assignment/-/work_items/162 Types: Issue Tracking -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 14, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-15076', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-14T12:20:15.334764Z'} -
New CVE Received by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/vert-x3/vertx-web', 'vendor': 'Eclipse Foundation', 'product': 'Eclipse Vert.x', 'versions': [{'status': 'affected', 'version': '4.0.0', 'versionType': 'semver', 'lessThanOrEqual': '4.5.29'}, {'status': 'affected', 'version': '5.0.0', 'versionType': 'semver', 'lessThanOrEqual': '5.1.4'}], 'defaultStatus': 'unaffected'}] Added 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. Added CVSS V4.0 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:X/V:X/RE:X/U:X Added CWE CWE-346 Added Reference https://gitlab.eclipse.org/security/cve-assignment/-/work_items/162