Publish GHSA-v4w8-49pv-mf72

Author: advisory-database[bot]

advisories/github-reviewed/2026/01/GHSA-v4w8-49pv-mf72/GHSA-v4w8-49pv-mf72.json

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+{
+  "schema_version": "1.4.0",
+  "id": "GHSA-v4w8-49pv-mf72",
+  "modified": "2026-01-20T18:36:17Z",
+  "published": "2026-01-20T18:36:17Z",
+  "aliases": [
+    "CVE-2026-23842"
+  ],
+  "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.",
+  "severity": [
+    {
+      "type": "CVSS_V3",
+      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
+    }
+  ],
+  "affected": [
+    {
+      "package": {
+        "ecosystem": "PyPI",
+        "name": "chatterbot"
+      },
+      "ranges": [
+        {
+          "type": "ECOSYSTEM",
+          "events": [
+            {
+              "introduced": "0"
+            },
+            {
+              "fixed": "1.2.11"
+            }
+          ]
+        }
+      ],
+      "database_specific": {
+        "last_known_affected_version_range": "<= 1.2.10"
+      }
+    }
+  ],
+  "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"
+    }
+  ],
+  "database_specific": {
+    "cwe_ids": [
+      "CWE-400"
+    ],
+    "severity": "HIGH",
+    "github_reviewed": true,
+    "github_reviewed_at": "2026-01-20T18:36:17Z",
+    "nvd_published_at": "2026-01-19T19:16:04Z"
+  }
+}