Improper Authentication Affecting fast-mcp-telegram package, versions [,0.19.1)
Threat Intelligence
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The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published4 Jul 2026
- disclosed2 Jul 2026
- creditUnknown
Introduced: 2 Jul 2026
NewCVE-2026-52830 (opens in a new tab)How to fix?
Upgrade fast-mcp-telegram to version 0.19.1 or higher.
Overview
fast-mcp-telegram is a Multi-tenant Telegram gateway for AI agents — HTTP+stdio transport, 8 agent-optimized tools, MTProto User API
Affected versions of this package are vulnerable to Improper Authentication via the SessionFileTokenVerifier.verify_token process. An attacker can gain unauthorized access to the default Telegram account session by supplying a specially crafted bearer token containing path traversal sequences, allowing them to perform actions such as reading messages, sending messages, and making API calls as the compromised account.