Security incident · CVE-2026-111763
A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol.
Published Oct 20, 2026 · catalog updated Oct 21, 2026 · A2A Java SDK is
Last checked Nov 4, 2026. A connected source was read within the last 7 days.
Check if you run it
No confirmed exploitation is on record for CVE-2026-111763. EPSS is 0.14%. Act only if a listed version of A2A Java SDK is is installed.
Gaps on this record
- The stored product name is a package slug. The name on this page is taken from the title (A2A Java SDK is).
- No vendor fix or required action is stored. Compare the linked advisory before you change production.
- Severity
- Medium5.7
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.14%
- Remediation
- Version ranges on file
- Affected products
- Maven org.a2aproject.sdk:a2a-java-sdk-parent · maven org.a2aproject.sdk:a2a-java-sdk-parent
*Impact.** A malicious or compromised A2A agent can cause the client's API key credential to be forwarded to an arbitrary third-party server. The agent serves an AgentCard with an specifying a custom header name, then responds with an HTTP redirect. The JDK HttpClient follows the redirect and forwards the custom header containing the credential, since only the standard header may be stripped on cross-origin redirects. **Where.** in **What.** The field from the remote agent's AgentCard (untrusted, server-controlled data) is used directly as the HTTP header name when placing client credentials. Combined with 's policy, credentials under custom header names survive cross-origin redirects (only is stripped on newer JDKs), allowing a malicious agent to leak client credentials to third-party servers. Additionally, does not check that before placing the credential as a header. **Exploit scenario.** Client configures an API key credential for agent's security scheme . The malicious agent returns an AgentCard where includes as with and . places the credential in the header. The agent responds with HTTP 302 redirect to . follows the redirect, forwarding all custom headers including to . The attacker captures the client's credential. **Preconditions.** - Client application has configured API key credentials via for the agent's security scheme - The agent is malicious or compromised (controls its own AgentCard response) - The default is used (with ) - The JDK version does not strip custom headers on cross-origin redirects (all current versions) **Fix.** Validate the field against a whitelist of safe header names. Check that equals before placing the credential as a header. Consider using and implementing manual redirect handling that strips all authentication headers on cross-origin redirects. **Verification.** 2/3 lens verifiers confirmed.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- Maven org.a2aproject.sdk:a2a-java-sdk-parent0 → 1.3.0.Final
- maven org.a2aproject.sdk:a2a-java-sdk-parent< 1.3.0.Final
How to fix CVE-2026-111763
Upgrade
CVE-2026-111763 lists a fix boundary at 1.3.0.Final. Compare the installed build with that boundary before you change production.
Version check
Affected < 1.3.0.Final
Advisory
Open the cve_org record and follow its fix.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2026-111763. EPSS is 0.14%. Act only if a listed version of A2A Java SDK is is installed.
Which versions are affected?
Compare what you have installed with 0 → 1.3.0.Final, < 1.3.0.Final. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-522: Insufficiently Protected Credentials. EPSS 0.14%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Oct 20, 2026 · NIST NVD
Detected
A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, a malicious or compromised remote agent can cause the default JDK-based client to forward a configured API key to a third-party server. When a client application configures credentials through , in uses from the remote AgentCard directly as the HTTP header name containing the credential, without checkin
Oct 20, 2026 · NIST NVD
Updated
A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, a malicious or compromised remote agent can cause the default JDK-based client to forward a configured API key to a third-party server. When a client application configures credentials through , in uses from the remote AgentCard directly as the HTTP header name containing the credential, without checkin
Oct 21, 2026 · GitHub Advisory Database
Fix available
org.a2aproject.sdk:a2a-java-sdk-parent fixed in 1.3.0.Final
Oct 21, 2026 · GitHub Advisory Database
Fix available
org.a2aproject.sdk:a2a-java-sdk-parent fixed in 1.3.0.Final
Oct 21, 2026 · GitHub Advisory Database
Updated
*Impact.** A malicious or compromised A2A agent can cause the client's API key credential to be forwarded to an arbitrary third-party server. The agent serves an AgentCard with an specifying a custom header name, then responds with an HTTP redirect. The JDK HttpClient follows the redirect and forwards the custom header containing the credential, since only the standard header may be stripped on cr
Oct 21, 2026 · NIST NVD
Updated
A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, a malicious or compromised remote agent can cause the default JDK-based client to forward a configured API key to a third-party server. When a client application configures credentials through , in uses from the remote AgentCard directly as the HTTP header name containing the credential, without checkin
Sources
- CVE.orgVulnerability recordCVE-2026-111763
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2026-111763
30-day exploitation probability 0.14%
first.org - GitHub Advisory DatabasePackage advisoryGHSA-9rhm-2h4x-jwmx
GitHub Advisory Database record mirrored by OSV.
github.com - NIST NVDVulnerability recordCVE-2026-111763
A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, a malicious or compromised remote agent can cause the default JDK-based client to forward a configured API key to a third-party server. When a client application configures credentials
nvd.nist.gov - OpenSSF OSV / OSV ScannerPackage advisoryGHSA-9rhm-2h4x-jwmx
A2A Java SDK send client credentials under server-controlled HTTP header name, enabling leakage via redirect
osv.dev
References
Freshness
Last verified in this catalog Nov 4, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.
- GitHub Advisory DatabaseOct 23, 2026
- OpenSSF OSV / OSV ScannerOct 23, 2026
- FIRST EPSSOct 23, 2026
- CVE.orgOct 21, 2026
- NIST NVDOct 21, 2026