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CVE-2026-90820: Missing Authorization in a2aproject a2a-java

0
Medium
VulnerabilityCVE-2026-90820cvecve-2026-90820
Published: 09/14/2026 (09/14/2026, 20:45:11 UTC)
Source: CVE Database V5
Vendor/Project: a2aproject
Product: a2a-java

Description

A security vulnerability has been detected in a2aproject a2a-java 1.2.0. The impacted element is the function AuthorizationRequestHandlerDecorator.onListTasks of the file server-common/src/main/java/org/a2aproject/sdk/server/requesthandlers/AuthorizationRequestHandlerDecorator.java. Such manipulation leads to missing authorization. The attack can be launched remotely. Upgrading to version 1.3.0 is sufficient to resolve this issue. The name of the patch is e9a1abf9c90c02b16d17293afdc3cc2f555d63a6. The affected component should be upgraded.

CVSS v4.0

Score 5.3medium

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
Low
User Interaction
None
Vuln. Confidentiality
Low
Vuln. Integrity
None
Vuln. Availability
None
Subsq. Confidentiality
None
Subsq. Integrity
None
Subsq. Availability
None
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X

Affected software

a2aproject

a2a-java

Affected versions
=1.2.0
CPE configurations
cpe:2.3:a:a2aproject:a2a-java:*:*:*:*:*:*:*:*

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 09/14/2026, 21:03:21 UTC

Technical Analysis

The vulnerability CVE-2026-90820 affects a2aproject a2a-java version 1.2.0 specifically in the AuthorizationRequestHandlerDecorator.onListTasks function located in server-common/src/main/java/org/a2aproject/sdk/server/requesthandlers/AuthorizationRequestHandlerDecorator.java. This flaw results in missing authorization controls, enabling remote attackers to perform unauthorized actions. The issue is fixed by upgrading to version 1.3.0, with the patch identified by commit e9a1abf9c90c02b16d17293afdc3cc2f555d63a6.

Potential Impact

The vulnerability allows remote attackers to bypass authorization checks in the affected function, potentially leading to unauthorized access or actions within the application. The CVSS 4.0 base score is 5.3 (medium severity), reflecting network attack vector, low complexity, no privileges required, and no user interaction needed.

Mitigation Recommendations

Upgrade the affected component a2a-java from version 1.2.0 to version 1.3.0, which contains the official fix for this missing authorization vulnerability. No additional mitigation steps are indicated.

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Technical Details

Data Version
5.2
Assigner Short Name
VulDB
Date Reserved
2026-09-13T19:01:40.764Z
Cvss Version
4.0
State
PUBLISHED

Threat ID: 6aa85d5755bf5e2cf598a1cf

Added to database: 09/14/2026, 20:47:19 UTC

Last enriched: 09/14/2026, 21:03:21 UTC

Last updated: 09/15/2026, 05:01:22 UTC

Views: 4

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