CVE-2026-39889: Praisonai PraisonAI Has Unauthenticated SSE Event Vulnerability

HIGH
Advisory Identifier: GHSA-f292-66h9-fpmf
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CVSS 7.5
CWE-200
Published
Advisory Summary

CVE-2026-39889 is a HIGH (CVSS 7.5) praisonai has unauthenticated sse event vulnerability (CWE-200: Exposure of Sensitive Information to an Unauthorized Actor) affecting Praisonai libraries in the PyPI ecosystem. The issue involves praisonai has unauthenticated sse event stream that exposes all agent activity in a2u server. Remediation is available by upgrading affected packages to version 4.5.115.

CVE-2026-39889 at a Glance

CVE Identifier CVE-2026-39889
GHSA Identifier GHSA-f292-66h9-fpmf
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
Affected Product Praisonai
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 7.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality High (C:H)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-39889

To remediate this vulnerability, upgrade all affected Praisonai dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

praisonai fixed: 4.5.115 
pip install praisonai>=4.5.115
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show praisonai

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-39889, inspect your installed packages using pip:

pip show praisonai

Analyze the terminal output to locate any version of Praisonai in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.5.115), your application is affected.

Note: The pip show praisonai command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor, where the product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. In Praisonai, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

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

CVE-2026-39889 Affected Praisonai Versions

1 component(s)
Fixed Versions:
4.5.115
Product / Package Ecosystem Affected Versions Fixed Version
praisonai
pypi/praisonai
PyPI
< 4.5.115
4.5.115

References

GitHub Advisory / Wiki ADVISORY
https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-f292-66h9-fpmf
NVD — CVE-2026-39889 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-39889
Praisonai Source Repository REPOSITORY
https://github.com/MervinPraison/PraisonAI
Praisonai Release RELEASE
https://github.com/MervinPraison/PraisonAI/releases/tag/v4.5.115

Frequently Asked Questions

What is CVE-2026-39889?
CVE-2026-39889 is a security vulnerability in Praisonai involving PraisonAI Has Unauthenticated SSE Event Stream that Exposes All Agent Activity in A2U Server under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor.
Which Praisonai versions are affected?
Affected versions include releases prior to 4.5.115 across affected packages: praisonai.
What version fixes CVE-2026-39889?
Upgrading to 4.5.115 (or the latest patched release for your respective branch) resolves the vulnerability.
Is praisonai affected?
Yes, praisonai is affected in releases prior to 4.5.115. Upgrade your dependency to 4.5.115 or later.
What is the CVSS score of CVE-2026-39889?
CVE-2026-39889 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.
What CWE is associated with CVE-2026-39889?
CVE-2026-39889 is classified under CWE-200: Exposure of Sensitive Information to an Unauthorized Actor (The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information.).
How can I check PyPI dependencies for CVE-2026-39889?
Run the dependency tree command: 'pip show praisonai'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-f292-66h9-fpmf",
  "modified" : "2026-04-09T14:29:15Z",
  "published" : "2026-04-08T19:21:14Z",
  "aliases" : [ "CVE-2026-39889" ],
  "summary" : "PraisonAI Has Unauthenticated SSE Event Stream that Exposes All Agent Activity in A2U Server",
  "details" : "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.\n\nThe create_a2u_routes() function registers the following endpoints with NO authentication checks:\n- GET  /a2u/info       — exposes server info and stream names\n- POST /a2u/subscribe  — creates event stream subscription\n- GET  /a2u/events/{stream_name} — streams ALL agent events\n- GET  /a2u/events/sub/{id}     — streams events for subscription\n- GET  /a2u/health     — health check\n\n\nAn unauthenticated attacker can:\n1. POST /a2u/subscribe → receive subscription_id\n2. GET /a2u/events/sub/{subscription_id} → receive live SSE stream \n   of all agent events including responses, tool calls, and thinking\n\nThis exposes sensitive agent activity including responses, internal  reasoning, and tool call arguments to any network attacker.\n\n<img width=\"1512\" height=\"947\" alt=\"image\" src=\"https://github.com/user-attachments/assets/3438f3ea-75ec-4978-9dd9-d9a6da42c248\" />\n\n<img width=\"1512\" height=\"571\" alt=\"image\" src=\"https://github.com/user-attachments/assets/ee3313f6-f522-48f7-9c06-e5e265c6aeb4\" />\n\n\n[1] POST /a2u/subscribe (no auth token)\n    Status: 200\n    Response: {\"subscription_id\":\"sub-a1ad8a6edd8b\",\"stream_name\":\"events\",\n    \"stream_url\":\"http://testserver/a2u/events/sub-a1ad8a6edd8b\"}\n    Got subscription_id: sub-a1ad8a6edd8b\n\n[2] GET /a2u/info (no auth token)\n    Status: 200\n    Response: {\"name\":\"A2U Event Stream\",\"version\":\"1.0.0\",\n    \"streams\":[\"events\"],\"event_types\":[\"agent.started\",\"agent.thinking\",\n    \"agent.tool_call\",\"agent.response\",\"agent.completed\",\"agent.error\"]}\n\n[3] GET /a2u/health (no auth token)  \n    Status: 200\n    Response: {\"status\":\"healthy\",\"active_subscriptions\":1,\"active_streams\":1}\n\n\nImpact: Attacker can subscribe and receive ALL agent events including responses, tool calls, and internal reasoning in real-time",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "praisonai"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.5.115"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.5.114"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/MervinPraison/PraisonAI/security/advisories/GHSA-f292-66h9-fpmf"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-39889"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/MervinPraison/PraisonAI"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/MervinPraison/PraisonAI/releases/tag/v4.5.115"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-200" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-08T19:21:14Z",
    "nvd_published_at" : "2026-04-08T21:17:01Z"
  }
}