Information Disclosure in praisonai (CVE-2026-39889)
Summary
Vulnerability in praisonai (CVE-2026-39889). Confidential information can be exposed externally. Exploitable via GET /a2u/info. Mitigation: upgrade to 4.5.115 or later.
Original description
The description as published by the source.
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:
- POST /a2u/subscribe → receive subscription_id
- 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.
[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":"h…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-39889 has been found in praisonai.
Attackers can target a specific entry point like GET /a2u/info over the network to misuse the product.
Confidential information can be exposed externally. CVSS score: 7.5/10.
What to do: upgrade praisonai to 4.5.115 or later.
If unsure, ask your IT team or search "praisonai CVE-2026-39889" on the vendor's site.
CVE-2026-39889 (praisonai) — CWE-200 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: GET /a2u/info / POST /a2u/subscribe / GET /a2u/events/{stream_name} / GET /a2u/events/sub/{id}
Patched: 4.5.115 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Information disclosure (CWE-200) exists in praisonai. Attackers reach the vulnerable code path via GET /a2u/info without authentication.
Check the vendor advisory for the affected versions of praisonai. Attack surface: GET /a2u/info / POST /a2u/subscribe / GET /a2u/events/{stream_name} / GET /a2u/events/sub/{id}.
Severity: High (CVSS 7.5/10). Confidential information can be exposed externally.
Update to 4.5.115.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual GET /a2u/info requests with malformed payloads or SQL meta-characters. Run grep -r 'praisonai' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'praisonai' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
praisonaiを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'GET /a2u/info' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
GET /a2u/infoへの異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。 -
3Apply patch patch
Upgrade praisonai to 4.5.115ステージング環境で 4.5.115 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against GET /a2u/info on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 2 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com