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5.8
MEDIUM CVSS 3.1
CVE-2026-111761
A2A Java SDK has Server-Side Request Forgery (SSRF) in push-notification delivery
Overview
Description

A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, BasePushNotificationSender in server-common sends task data to the URL in TaskPushNotificationConfig without destination validation, scheme restrictions, or bounds on redirects. InMemoryPushNotificationConfigStore.setInfo stores the URL verbatim, and onCreateTaskPushNotificationConfig does not validate the destination. In the default deployment with push notifications enabled, an unauthenticated caller can register a destination through an inline SendMessage configuration or CreateTaskPushNotificationConfig for an existing task, causing task status and artifact updates to send requests from the server's network position to loopback, private, link-local cloud-metadata, IPv6 unique-local, unspecified, or multicast destinations where routing permits. JdkA2AHttpClient and VertxA2AHttpClient follow redirects, allowing a webhook redirect to bypass creation-time destination checks and convert a POST into a GET; hostname-only checks also do not prevent DNS rebinding. Direct POST delivery can push attacker-influenced task data into internal services, whereas a redirected POST-to-GET request drops the body. The sender discards the fetched response and does not expose delivery success or failure, so the demonstrated behavior does not provide response read-back. No credentials or user interaction are required. This issue is fixed in version 1.3.0.Final.

Details
INFO

Published Date :

Oct. 20, 2026, 3:17 p.m.

Last Modified :

Oct. 22, 2026, 10:18 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Impact
Affected Products

The following products are affected by CVE-2026-111761 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 A2aproject a2a-java
: Total Affected Vendor : 1 | Products : 1
Scoring
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 134c704f-9b21-4f2e-91b3-4a467353bcc0
CVSS 3.1 MEDIUM MITRE-CVE
CVSS 3.1 MEDIUM [email protected]
Solution
Update the Agent2Agent Java SDK to version 1.3.0.Final or later to fix the SSRF vulnerability.
  • Update the Agent2Agent Java SDK to 1.3.0.Final.
  • Apply vendor patches for older versions if available.
  • Validate all external URLs and destinations.
  • Implement strict destination and redirect controls.
References
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-2026-111761.

URL Resource
https://github.com/a2aproject/a2a-java/commit/b855b2ae37e4bf23f73e7746ce166fbc5a0b8b5b
https://github.com/a2aproject/a2a-java/pull/1096
https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final
https://github.com/a2aproject/a2a-java/security/advisories/GHSA-q78c-5jjq-57g8
https://github.com/a2aproject/a2a-java/security/advisories/GHSA-q78c-5jjq-57g8
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-111761 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-2026-111761 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-2026-111761 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-111761 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 Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 22, 2026

    Action Type Old Value New Value
    Added Reference https://github.com/a2aproject/a2a-java/security/advisories/GHSA-q78c-5jjq-57g8
    Added SSVC {'id': 'CVE-2026-111761', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-10-22T21:30:10.957773Z'}
  • New CVE Received by [email protected]

    Oct. 20, 2026

    Action Type Old Value New Value
    Added Description A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, BasePushNotificationSender in server-common sends task data to the URL in TaskPushNotificationConfig without destination validation, scheme restrictions, or bounds on redirects. InMemoryPushNotificationConfigStore.setInfo stores the URL verbatim, and onCreateTaskPushNotificationConfig does not validate the destination. In the default deployment with push notifications enabled, an unauthenticated caller can register a destination through an inline SendMessage configuration or CreateTaskPushNotificationConfig for an existing task, causing task status and artifact updates to send requests from the server's network position to loopback, private, link-local cloud-metadata, IPv6 unique-local, unspecified, or multicast destinations where routing permits. JdkA2AHttpClient and VertxA2AHttpClient follow redirects, allowing a webhook redirect to bypass creation-time destination checks and convert a POST into a GET; hostname-only checks also do not prevent DNS rebinding. Direct POST delivery can push attacker-influenced task data into internal services, whereas a redirected POST-to-GET request drops the body. The sender discards the fetched response and does not expose delivery success or failure, so the demonstrated behavior does not provide response read-back. No credentials or user interaction are required. This issue is fixed in version 1.3.0.Final.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
    Added CWE CWE-918
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/111xxx/CVE-2026-111761.json">CVE-2026-111761</a>
    Added Reference https://github.com/a2aproject/a2a-java/commit/b855b2ae37e4bf23f73e7746ce166fbc5a0b8b5b
    Added Reference https://github.com/a2aproject/a2a-java/pull/1096
    Added Reference https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final
    Added Reference https://github.com/a2aproject/a2a-java/security/advisories/GHSA-q78c-5jjq-57g8
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
CVSS
Vulnerability Scoring Details
Base CVSS Score: 5.8
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact