CVE-2026-23842
ChatterBot Vulnerable to Denial of Service via Database Connection Pool Exhaustion
Impact
### 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() 4. 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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | chatterbot | <= 1.2.10 | 1.2.11 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Chatterbot | Chatterbot | before 1.2.11 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/gunthercox/ChatterBot/commit/de89fe648139f8eeacc998ad4524fab291a378cf
- https://github.com/gunthercox/ChatterBot/pull/2432
- https://github.com/gunthercox/ChatterBot/releases/tag/1.2.11
- https://github.com/gunthercox/ChatterBot/security/advisories/GHSA-v4w8-49pv-mf72
- https://github.com/user-attachments/assets/4ee845c4-b847-4854-84ec-4b2fb2f7090f
- https://github.com/advisories/GHSA-v4w8-49pv-mf72
- https://nvd.nist.gov/vuln/detail/CVE-2026-23842