Security fix · CVE-2026-111761

A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol.

Q: 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.

Q: What should an analyst verify?

CWE-918: Server-Side Request Forgery (SSRF). EPSS 0.59%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Published Oct 20, 2026 · catalog updated Oct 20, 2026 · A2A Java SDK is

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-111761. EPSS is 0.59%. 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: Medium5.8
Known exploitation: Not in CISA/VulnCheck KEV
EPSS: 0.59%
Remediation: Version ranges on file
Affected products: Maven org.a2aproject.sdk:a2a-java-sdk-server-common · maven org.a2aproject.sdk:a2a-java-sdk-server-common

--- - **Ecosystem:** Maven - **Affected package:** (push-notification delivery) - **Affected versions:** (and on prior to the fix) - **Patched version:** _(the release that carries the fix)_ - **CWE:** CWE-918 (Server-Side Request Forgery) - **Severity:** High - **CVSS v3.1:** (5.8, Moderate) --- ## Summary An **unauthenticated** attacker can coerce the a2a-java server into issuing HTTP requests to arbitrary internal and cloud-metadata endpoints from the server's own network position — a Server-Side Request Forgery reachable in the default deployment with no credentials, no user interaction, and a single request. The behaviour is the shipped default, not a misconfiguration. ## Details (in ) POSTs task data to the URL stored on a task's with no validation of the destination: no block on loopback, RFC1918, link-local ( , including the metadata address), unique-local, unspecified, or multicast ranges; no scheme restriction; and no bound on redirects. stores the URL verbatim and does not check it either. Both shipped HTTP clients follow redirects ( → , → ), so a creation-time URL allowlist is bypassable: an attacker webhook answers and the client follows it. A hostname check is likewise defeated by DNS rebinding. A correct guard must validate the *resolved* IP of every hop at connection time, not the URL string. ## Exploitation Demonstrated end-to-end against a running server (default wiring, unauthenticated caller): - **Arbitrary internal reachability.** The attacker picks the destination and the server issues the request from inside the trust boundary. Delivery to loopback and to a real RFC1918 LAN address was exercised at runtime; because the code applies no destination filtering of any kind, the same path reaches link-local / metadata ( ) and other internal ranges wherever network routing permits. - **Allowlist + method bypass via redirect.** A from the attacker's webhook reaches destinations a creation-time allowlist would block, and a on a is followed as a — so GE

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-server-common0 → 1.3.0.Final
maven org.a2aproject.sdk:a2a-java-sdk-server-common< 1.3.0.Final

How to fix CVE-2026-111761

Upgrade
CVE-2026-111761 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-2026-111761. EPSS is 0.59%. 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-918: Server-Side Request Forgery (SSRF). EPSS 0.59%. 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, BasePushNotificationSender in server-common sends task data to the URL in TaskPushNotificationConfig without destination validation, scheme restrictions, or bounds on redirects. InMemoryPushNotificationConfigStore.setInfo stores the URL verbatim, and onCreateTaskPushNotificationConfig does not validate
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, BasePushNotificationSender in server-common sends task data to the URL in TaskPushNotificationConfig without destination validation, scheme restrictions, or bounds on redirects. InMemoryPushNotificationConfigStore.setInfo stores the URL verbatim, and onCreateTaskPushNotificationConfig does not validate
Oct 20, 2026 · GitHub Advisory Database
Fix available
org.a2aproject.sdk:a2a-java-sdk-server-common fixed in 1.3.0.Final
Oct 20, 2026 · GitHub Advisory Database
Fix available
org.a2aproject.sdk:a2a-java-sdk-server-common fixed in 1.3.0.Final
Oct 20, 2026 · GitHub Advisory Database
Updated
--- - **Ecosystem:** Maven - **Affected package:** (push-notification delivery) - **Affected versions:** (and on prior to the fix) - **Patched version:** _(the release that carries the fix)_ - **CWE:** CWE-918 (Server-Side Request Forgery) - **Severity:** High - **CVSS v3.1:** (5.8, Moderate) --- ## Summary An **unauthenticated** attacker can coerce the a2a-java server into issuing HTTP requests t

Sources

CVE.orgVulnerability recordCVE-2026-111761
Official CVE identifier
cve.org
FIRST EPSSExploitation probabilityCVE-2026-111761
30-day exploitation probability 0.59%
first.org
GitHub Advisory DatabasePackage advisoryGHSA-q78c-5jjq-57g8
GitHub Advisory Database record mirrored by OSV.
github.com
NIST NVDVulnerability recordCVE-2026-111761
A2A Java SDK is the official Java SDK for the Agent2Agent (A2A) Protocol. Prior to 1.3.0.Final, BasePushNotificationSender in server-common sends task data to the URL in TaskPushNotificationConfig without destination validation, scheme restrictions, or bounds on redirects. InMemo
nvd.nist.gov
OpenSSF OSV / OSV ScannerPackage advisoryGHSA-q78c-5jjq-57g8
A2A Java SDK has Server-Side Request Forgery (SSRF) in push-notification delivery
osv.dev

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

FIRST EPSSNov 6, 2026
GitHub Advisory DatabaseOct 23, 2026
OpenSSF OSV / OSV ScannerOct 23, 2026
CVE.orgOct 21, 2026
NIST NVDOct 21, 2026

Priority score

10/100

Evidence confidence: High

Several independent sources name this vulnerability.

Confirmed exploitation0/30
EPSS probability1/20
CVSS severity9/15
Public exploit0/10
Internet exposure0/10
Product prevalence0/5
Detection0/5
Threat research0/5

Decision signals

Four separate signals — do not infer one from another.

Medium

CVSS severity
5.8 v3.1
Technical impact. Separate from exploitation likelihood.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
EPSS probability
0.59% · p47.72%
Estimated probability of exploitation within 30 days (FIRST).
Known exploitation
No verified KEV listing
Evidence from CISA KEV or VulnCheck KEV only — not from EPSS alone.
Patch availability
Version ranges on file
Affected version ranges suggest a fixed boundary. Verify against the vendor advisory for your release.

Stacks

Maven

Weakness

CWE-918
Server-Side Request Forgery (SSRF)
MITRE definition

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