{"id":"CVE-2026-23842","aliases":["GHSA-v4w8-49pv-mf72","PYSEC-2026-1244"],"url":"https://o3.security/vulnerability/CVE-2026-23842","summary":"ChatterBot has Denial of Service via Database Connection Pool Exhaustion","details":"### Summary\nChatterBot versions up to 1.2.10 are vulnerable to a denial-of-service condition caused by improper database session and connection pool management. Concurrent invocations of the get_response() method can exhaust the underlying SQLAlchemy connection pool, resulting in persistent service unavailability and requiring a manual restart to recover.\n\n### Details\nChatterBot relies on SQLAlchemy for database access and uses a connection pool with default limits. The get_response() method does not enforce concurrency limits, rate limiting, or explicit session lifecycle controls.\n\nWhen multiple threads concurrently invoke get_response(), database connections are rapidly consumed and not released in a timely manner. This leads to exhaustion of the SQLAlchemy QueuePool, causing subsequent requests to block and eventually fail with a TimeoutError.\n\nThis issue can be triggered without authentication in deployments where ChatterBot is exposed as a chatbot service, making it exploitable by remote attackers to cause denial of service.\n\nPoC Video: \nhttps://github.com/user-attachments/assets/4ee845c4-b847-4854-84ec-4b2fb2f7090f\n\n### PoC\n1. Install ChatterBot version 1.2.10.\n2. Use the default database configuration (SQLite / SQLAlchemy).\n3. Run the following Python script to invoke concurrent requests:\n\nfrom chatterbot import ChatBot\nimport threading\n\nbot = ChatBot(\"dos-test\")\n\ndef attack():\n    bot.get_response(\"hello\")\n\nthreads = []\nfor _ in range(30):\n    t = threading.Thread(target=attack)\n    t.start()\n    threads.append(t)\n\nfor t in threads:\n    t.join()\n\n4. Observe that the application becomes unresponsive and raises SQLAlchemy TimeoutError exceptions indicating exhaustion of the connection pool.\n\n### Impact\nThis vulnerability allows an attacker to trigger a denial-of-service condition by exhausting the database connection pool. Once triggered, the chatbot becomes unresponsive to legitimate users and requires a manual restart to restore functionality.\n\nAll deployments of ChatterBot version 1.2.10 or earlier that allow concurrent access to the get_response() method are impacted.","published":"2026-01-19T18:39:37.059Z","modified":"2026-08-12T03:51:34.413562270Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"chatterbot","fixedVersion":"1.2.11"}],"fix":{"url":"https://github.com/gunthercox/ChatterBot/commit/de89fe648139f8eeacc998ad4524fab291a378cf","label":"gunthercox/ChatterBot@de89fe6"},"references":[{"type":"WEB","url":"https://github.com/gunthercox/ChatterBot/releases/tag/1.2.11"},{"type":"WEB","url":"https://github.com/user-attachments/assets/4ee845c4-b847-4854-84ec-4b2fb2f7090f"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23842.json"},{"type":"ADVISORY","url":"https://github.com/gunthercox/ChatterBot/security/advisories/GHSA-v4w8-49pv-mf72"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-23842"},{"type":"FIX","url":"https://github.com/gunthercox/ChatterBot/commit/de89fe648139f8eeacc998ad4524fab291a378cf"},{"type":"FIX","url":"https://github.com/gunthercox/ChatterBot/pull/2432"},{"type":"PACKAGE","url":"https://github.com/gunthercox/ChatterBot"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:34.413562270Z"}}