---
id: "CVE-2026-111762"
kind: "vulnerability"
aliases: ["CVE-2026-111762", "GHSA-x32g-jvvm-4725"]
title: "A2A Java SDK: Push notification credentials logged in cleartext on protobuf parse failure"
severity: "medium"
cvss: 5.7
epss: 0.0017399999778717756
exploited: false
status: "open"
category: "package"
products: [{"name": "org.a2aproject.sdk:a2a-java-sdk-transport-rest", "fixed": ["1.3.0.Final"], "affected": "< 1.3.0.Final", "ecosystem": "maven"}]
ecosystems: ["maven"]
tags: ["a2a", "cwe-532", "java", "package", "push-notifications", "self-hosted"]
not_affected_if: ["push-notifications-disabled", "version-1.3.0-or-later"]
published_at: "2026-10-20T15:17:13+00:00"
first_seen_at: "2026-10-23T19:11:32+00:00"
updated_at: "2026-10-23T21:57:20+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-x32g-jvvm-4725", "first_seen_at": "2026-10-23T19:11:32+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-111762", "first_seen_at": "2026-10-23T21:57:20+00:00"}]
---

# A2A Java SDK: Push notification credentials logged in cleartext on protobuf parse failure

The A2A Java SDK REST transport logs the full request body at SEVERE level when protobuf parsing fails, so push notification bearer tokens and authentication credentials sent by clients end up in server log files in cleartext. Anyone who can read those logs can reuse the credentials to call the client's push notification endpoints and send forged task updates.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- maven:org.a2aproject.sdk:a2a-java-sdk-transport-rest affected < 1.3.0.Final fixed 1.3.0.Final

## How to check

Check whether the project depends on maven:org.a2aproject.sdk:a2a-java-sdk-transport-rest and what version is resolved (below 1.3.0.Final is affected).
Search server logs for SEVERE entries from RestHandler that contain "token" or "credentials" fields.

## Fix

Upgrade org.a2aproject.sdk:a2a-java-sdk-transport-rest to 1.3.0.Final or later.
Rotate any push notification tokens and authentication credentials that were sent to affected servers, and purge or restrict access to logs that contain them.

## Timeline

- 2026-10-23T19:11:32+00:00 ghsa https://github.com/advisories/GHSA-x32g-jvvm-4725
- 2026-10-23T21:57:20+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-111762

## From the sources

### *Impact.** Push notification bearer tokens and authentication credentials submitted by clients are written to server log files in cleartext. Any operator, log aggregation system, or attacker with log access can read these secrets and use them to authenticate to the client's push notification endpoints, potentially sending forged task status updates.

**Where.** `transport/rest/src/main/java/org/a2aproject/sdk/transport/rest/handler/RestHandler.java:676` in `parseRequestBody`

**What.** The `parseRequestBody` method logs the entire JSON request body at `SEVERE` level when `JsonFormat.parser().merge()` throws `InvalidProtocolBufferException`. This method is called from `createTaskPushNotificationConfiguration` (line 377), where the body contains client-supplied push notification bearer tokens (field `token`) and authentication credentials (field `authentication.credentials`). These secrets are written to server log files in full.

**Exploit scenario.** A client creates a push notification configuration by POSTing to `/v1/tenants/{tenant}/tasks/{taskId}/pushNotificationConfigs` with a body containing `{"url": "https://client.example.com/webhook", "token": "secret-bearer-token", "authentication": {"scheme": "Bearer", "credentials": "oauth-access-token"}, "extraField": "value"}`. The extra field causes `JsonFormat.parser().merge()` to throw `InvalidProtocolBufferException`. The entire body including `secret-bearer-token` and `oauth-access-token` is logged at SEVERE level. An attacker with log access retrieves the cleartext credentials.

**Preconditions.**
- Attacker must have access to server log files (centralized logging, log aggregation, shared infrastructure, or insider access)
- Push notification capability must be enabled
- A request body must fail protobuf deserialization while being valid JSON (unknown fields with strict parsing, schema mismatches)

**Fix.** Do not log the raw request body. Log only a sanitized summary — body length and content type, not content. Replace the log call with something like: `log.log(Level.SEVERE, "Error parsing JSON request body (length={0})", body != null ? body.length() : 0)`.

**Verification.** 3/3 lens verifiers confirmed.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_