Summary
A2A Java SDK: Push notification credentials logged in cleartext on protobuf parse failure
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.
Impact
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
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Frequently Asked Questions
- What is CVE-2026-111762? CVE-2026-111762 is a medium-severity security vulnerability in org.a2aproject.sdk:a2a-java-sdk-transport-rest (maven), affecting versions < 1.3.0.Final. It is fixed in 1.3.0.Final.
- Which versions of org.a2aproject.sdk:a2a-java-sdk-transport-rest are affected by CVE-2026-111762? org.a2aproject.sdk:a2a-java-sdk-transport-rest (maven) versions < 1.3.0.Final is affected.
- Is there a fix for CVE-2026-111762? Yes. CVE-2026-111762 is fixed in 1.3.0.Final. Upgrade to this version or later.
- Is CVE-2026-111762 exploitable, and should I be worried? Whether CVE-2026-111762 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-111762 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-111762? Upgrade
org.a2aproject.sdk:a2a-java-sdk-transport-restto 1.3.0.Final or later.