NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
🐍
🐍 PyPI
Not in CISA KEV
HIGH severity

CVE-2026-39889 — praisonai

HIGH

CVE-2026-39889 is a high-severity (CVSS 7.5) Information Exposure vulnerability in praisonai. A fix is available for praisonai — see the affected versions and patch details below.

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

Also known asGHSA-f292-66h9-fpmfPYSEC-2026-2911
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Nov 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-39889.

EPSS Exploitation Probability

via FIRST.org ↗
0.4%probability of exploitation in next 30 days
Lower Risk+0.02%
Lower risk than most CVEs38th percentile — riskier than 38% of all scored CVEsHighest risk
0.00%0.33%0.65%0.98%0.0%0.4%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
🐍praisonai

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

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

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIpraisonaiall versions4.5.115pip install --upgrade 'praisonai==4.5.115'

Affected Products

1 product · 1 configurations
Application
praisonaipraison
≤ 4.5.114
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for praisonai, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update praisonai to 4.5.115 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-39889 is resolved across your whole dependency graph.

  3. Workarounds

    Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

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
O3 Security · Impact-Aware SCA

Is CVE-2026-39889 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2026-39889: praisonai — Fixed in 4.5.115