id: PYSEC-2026-1244
published: "2026-07-07T16:03:19.183779Z"
modified: "2026-07-07T17:23:54.115855Z"
aliases:
- CVE-2026-23842
- GHSA-v4w8-49pv-mf72
summary: ChatterBot Vulnerable to 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."
affected:
- package:
    name: chatterbot
    ecosystem: PyPI
    purl: pkg:pypi/chatterbot
  ranges:
  - type: ECOSYSTEM
    events:
    - introduced: "0"
    - fixed: 1.2.11
  versions:
  - 0.0.0
  - 0.0.1
  - 0.0.2
  - 0.0.3
  - 0.0.4
  - 0.0.5
  - 0.1.0
  - 0.1.1
  - 0.1.2
  - 0.2.0
  - 0.2.1
  - 0.2.2
  - 0.2.3
  - 0.2.4
  - 0.2.5
  - 0.2.6
  - 0.2.7
  - 0.2.8
  - 0.2.9
  - 0.3.0
  - 0.3.1
  - 0.3.2
  - 0.3.3
  - 0.3.4
  - 0.3.5
  - 0.3.6
  - 0.3.7
  - 0.4.0
  - 0.4.1
  - 0.4.10
  - 0.4.11
  - 0.4.12
  - 0.4.13
  - 0.4.2
  - 0.4.3
  - 0.4.4
  - 0.4.5
  - 0.4.6
  - 0.4.7
  - 0.4.8
  - 0.4.9
  - 0.5.0
  - 0.5.1
  - 0.5.2
  - 0.5.3
  - 0.5.4
  - 0.5.5
  - 0.6.0
  - 0.6.1
  - 0.6.2
  - 0.6.3
  - 0.7.0
  - 0.7.1
  - 0.7.2
  - 0.7.3
  - 0.7.4
  - 0.7.5
  - 0.7.6
  - 0.8.0
  - 0.8.1
  - 0.8.2
  - 0.8.3
  - 0.8.4
  - 0.8.5
  - 0.8.6
  - 0.8.7
  - 1.0.0
  - 1.0.0a1
  - 1.0.0a2
  - 1.0.0a3
  - 1.0.0a4
  - 1.0.1
  - 1.0.2
  - 1.0.3
  - 1.0.4
  - 1.0.5
  - 1.0.7
  - 1.0.8
  - 1.1.0
  - 1.1.0a7
  - 1.2.0
  - 1.2.1
  - 1.2.10
  - 1.2.2
  - 1.2.3
  - 1.2.4
  - 1.2.5
  - 1.2.6
  - 1.2.7
  - 1.2.8
  - 1.2.9
references:
- type: WEB
  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: WEB
  url: https://github.com/gunthercox/ChatterBot/pull/2432
- type: WEB
  url: https://github.com/gunthercox/ChatterBot/commit/de89fe648139f8eeacc998ad4524fab291a378cf
- type: PACKAGE
  url: https://github.com/gunthercox/ChatterBot
- 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: PACKAGE
  url: https://pypi.org/project/chatterbot
- type: ADVISORY
  url: https://github.com/advisories/GHSA-v4w8-49pv-mf72
severity:
- type: CVSS_V3
  score: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H