Every CVE Search/ Get API key

CVE-2026-39889

PraisonAI has Unauthenticated SSE Event Stream Exposes All Agent Activity in A2U Server

7.5 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
None
Availability
None

Exploit likelihood

0.43%Up 0.4 points since Apr 9, 2026
90%50%10%1%

What each source reports

CVE List Score used 7.5

PraisonAI has Unauthenticated SSE Event Stream Exposes All Agent Activity in A2U Server

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.

Record
CVE-2026-39889
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-200
Updated
2026-11-02
EUVDEUVD-2026-20636 7.5

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.

Record
EUVD-2026-20636
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-f292-66h9-fpmf 7.5

PraisonAI Has Unauthenticated SSE Event Stream that Exposes All Agent Activity in A2U Server

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

Record
GHSA-f292-66h9-fpmf
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-200
Updated
2026-11-02
NVD 7.5

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.

Record
CVE-2026-39889
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-200
Updated
2026-11-02
OSV 7.5

PraisonAI has Unauthenticated SSE Event Stream Exposes All Agent Activity in A2U Server

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.

Record
CVE-2026-39889
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-200
Updated
2026-11-02
OSVGHSA-f292-66h9-fpmf 7.5

PraisonAI Has Unauthenticated SSE Event Stream that Exposes All Agent Activity in A2U Server

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

Record
GHSA-f292-66h9-fpmf
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness
CWE-200
Updated
2026-11-02
OSVPYSEC-2026-2911 7.5

PraisonAI Has Unauthenticated SSE Event Stream that Exposes All Agent Activity in A2U Server

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

Record
PYSEC-2026-2911
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
praisonai
PyPI
 through 4.5.114
4.5.115
praisonai
PyPI
 before 4.5.115, plus listed versions
0.0.10.0.100.0.110.0.120.0.13
Show 45 moreShow less
0.0.140.0.150.0.160.0.170.0.180.0.190.0.20.0.200.0.210.0.220.0.230.0.240.0.250.0.260.0.270.0.280.0.290.0.30.0.300.0.310.0.320.0.330.0.340.0.350.0.360.0.370.0.380.0.390.0.40.0.400.0.410.0.420.0.430.0.440.0.450.0.460.0.470.0.480.0.490.0.50.0.500.0.520.0.530.0.540.0.55
4.5.115

History

History
RecordedChangedSources
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-39889 is a high vulnerability (CVSS 7.5) in Mervinpraison Praisonai, published April 8, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in praisonai 4.5.115.

References

This page doesn't list everything

Left out here: 623 versions. The JSON record has them.

Pages All vulnerabilities Browse Docs Sources Guide Get API key
MoveEnter Open