PYSEC-2026-1244

Vulnerability from pysec - Published: 2026-07-07 16:03 - Updated: 2026-07-07 17:23
VLAI
Details

Summary

ChatterBot 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.

Details

ChatterBot 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.

When 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.

This 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.

PoC Video: https://github.com/user-attachments/assets/4ee845c4-b847-4854-84ec-4b2fb2f7090f

PoC

  1. Install ChatterBot version 1.2.10.
  2. Use the default database configuration (SQLite / SQLAlchemy).
  3. Run the following Python script to invoke concurrent requests:

from chatterbot import ChatBot import threading

bot = ChatBot("dos-test")

def attack(): bot.get_response("hello")

threads = [] for _ in range(30): t = threading.Thread(target=attack) t.start() threads.append(t)

for t in threads: t.join()

  1. Observe that the application becomes unresponsive and raises SQLAlchemy TimeoutError exceptions indicating exhaustion of the connection pool.

Impact

This 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.

All deployments of ChatterBot version 1.2.10 or earlier that allow concurrent access to the get_response() method are impacted.

Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Impacted products
Name purl
chatterbot pkg:pypi/chatterbot
Aliases
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "chatterbot",
        "purl": "pkg:pypi/chatterbot"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "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"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-23842",
    "GHSA-v4w8-49pv-mf72"
  ],
  "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.",
  "id": "PYSEC-2026-1244",
  "modified": "2026-07-07T17:23:54.115855Z",
  "published": "2026-07-07T16:03:19.183779Z",
  "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": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "ChatterBot Vulnerable to Denial of Service via Database Connection Pool Exhaustion"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.