CVE-2026-39889
highpriority · track · 0EPSS 0.004 · 36 %ileEUUSEPSS · scored 2026-10-27
PraisonAI is a multi-agent teams system. Prior to 4.5.115, the A2U (Agent-to-User) event stream server in PraisonAI exposes all agent activity without authentication. The create_a2u_routes() function registers the following endpoints with NO authentication checks: /a2u/info, /a2u/subscribe, /a2u/events/{stream_name}, /a2u/events/sub/{id}, and /a2u/health. This vulnerability is fixed in 4.5.115.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–7.5
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (3)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- GHSA-f292-66h9-fpmfPraisonAI Has Unauthenticated SSE Event Stream that Exposes All Agent Activity in A2U Server2026-04-08ghsa · osvUS
The A2U (Agent-to-User) event stream server in PraisonAI exposes all agent activity without authentication. This is a separate component from the gateway server fixed in CVE-2026-34952. The create_a2u_routes() function registers the following endpoints with NO authentication checks: - GET /a2u/info — exposes server info and stream names - POST /a2u/subscribe — creates event stream subscription - GET /a2u/events/{stream_name} — streams ALL agent events - GET /a2u/events/sub/{id} — streams events for subscription - GET /a2u/health — health check An unauthenticated attacker can: 1. POST /a2u/subscribe → receive subscription_id 2. GET /a2u/events/sub/{subscription_id} → receive live SSE stream of all agent events including responses, tool calls, and thinking This exposes sensitive agent activity including responses, internal reasoning, and tool call arguments to any network attacker. <img width="1512" height="947" alt="image" src="https://github.com/user-attachments/assets/3438f3ea-75ec-4978-9dd9-d9a6da42c248" /> <img width="1512" height="571" alt="image" src="https://github.com/user-attachments/assets/ee3313f6-f522-48f7-9c06-e5e265c6aeb4" /> [1] POST /a2u/subscribe (no auth token) Status: 200 Response: {"subscription_id":"sub-a1ad8a6edd8b","stream_name":"events", "stream_url":"http://testserver/a2u/events/sub-a1ad8a6edd8b"} Got subscription_id: sub-a1ad8a6edd8b [2] GET /a2u/info (no auth token) Status: 200 Response: {"name":"A2U Event Stream","version":"1.0.0", "streams":["events"],"event_types":["agent.started","agent.thinking", "agent.tool_call","agent.response","agent.completed","agent.error"]} [3] GET /a2u/health (no auth token) Status: 200 Response: {"status":"healthy","active_subscriptions":1,"active_streams":1} Impact: Attacker can subscribe and receive ALL agent events including responses, tool calls, and internal reasoning in real-time
- PYSEC-2026-2911PraisonAI Has Unauthenticated SSE Event Stream that Exposes All Agent Activity in A2U Server2026-07-13vendor · osvUS
The A2U (Agent-to-User) event stream server in PraisonAI exposes all agent activity without authentication. This is a separate component from the gateway server fixed in CVE-2026-34952. The create_a2u_routes() function registers the following endpoints with NO authentication checks: - GET /a2u/info — exposes server info and stream names - POST /a2u/subscribe — creates event stream subscription - GET /a2u/events/{stream_name} — streams ALL agent events - GET /a2u/events/sub/{id} — streams events for subscription - GET /a2u/health — health check An unauthenticated attacker can: 1. POST /a2u/subscribe → receive subscription_id 2. GET /a2u/events/sub/{subscription_id} → receive live SSE stream of all agent events including responses, tool calls, and thinking This exposes sensitive agent activity including responses, internal reasoning, and tool call arguments to any network attacker. <img width="1512" height="947" alt="image" src="https://github.com/user-attachments/assets/3438f3ea-75ec-4978-9dd9-d9a6da42c248" /> <img width="1512" height="571" alt="image" src="https://github.com/user-attachments/assets/ee3313f6-f522-48f7-9c06-e5e265c6aeb4" /> [1] POST /a2u/subscribe (no auth token) Status: 200 Response: {"subscription_id":"sub-a1ad8a6edd8b","stream_name":"events", "stream_url":"http://testserver/a2u/events/sub-a1ad8a6edd8b"} Got subscription_id: sub-a1ad8a6edd8b [2] GET /a2u/info (no auth token) Status: 200 Response: {"name":"A2U Event Stream","version":"1.0.0", "streams":["events"],"event_types":["agent.started","agent.thinking", "agent.tool_call","agent.response","agent.completed","agent.error"]} [3] GET /a2u/health (no auth token) Status: 200 Response: {"status":"healthy","active_subscriptions":1,"active_streams":1} Impact: Attacker can subscribe and receive ALL agent events including responses, tool calls, and internal reasoning in real-time
also known as (6)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (5)
External citations — patches, advisories, analysis.
- https://access.redhat.com/security/cve/cve-2026-39889cnnvd
- https://github.com/MervinPraison/PraisonAI/releasesPatchcnnvd
- https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-f292-66h9-fpmfcnnvd
- https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-f292-66h9-fpmfenisa_euvd
- https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-f292-66h9-fpmfVendor Advisorynvd
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