PYPI · JULY 2026 · EARLY WARNING

fast-mcp-telegram Package Vulnerability: Bearer Token Path Traversal

EARLY WARNING · UNCONFIRMED. This page describes a developing threat that 0Day surfaced from early signals and has not yet independently confirmed. Details may change. Always verify against the primary sources before acting.
Severity
HIGH
Affected component
fast-mcp-telegram (pypi)
Affected versions
< 0.19.1 or >= 0.0.1, <= 0.0.1 or >= 0.1.1, <= 0.1.1 or >= 0.1.2, <= 0.1.2 or >= 0.1.3, <= 0.1.3 or >= 0.1.4, <= 0.1.4 or >= 0.10.0, <= 0.10.0 or >= 0.10.1, <= 0.10.1 or >= 0.10.2, <= 0.10.2 or >= 0.11.0, <= 0.11.0 or >= 0.11.1, <= 0.11.1 or >= 0.12.0, <= 0.12.0 or >= 0.12.1, <= 0.12.1 or >= 0.12.2, <= 0.12.2 or >= 0.12.3, <= 0.12.3 or >= 0.13.0, <= 0.13.0 or >= 0.13.1, <= 0.13.1 or >= 0.14.0, <= 0.14.0 or >= 0.14.1, <= 0.14.1 or >= 0.14.2, <= 0.14.2 or >= 0.15.0, <= 0.15.0 or >= 0.16.0, <= 0.16.0 or >= 0.16.1, <= 0.16.1 or >= 0.16.2, <= 0.16.2 or >= 0.16.3, <= 0.16.3 or >= 0.16.4, <= 0.16.4 or >= 0.16.5, <= 0.16.5 or >= 0.16.6, <= 0.16.6 or >= 0.17.0, <= 0.17.0 or >= 0.17.1, <= 0.17.1 or >= 0.17.2, <= 0.17.2 or >= 0.17.3, <= 0.17.3 or >= 0.18.0, <= 0.18.0 or >= 0.18.1, <= 0.18.1 or >= 0.19.0, <= 0.19.0 or >= 0.2.0, <= 0.2.0 or >= 0.2.1, <= 0.2.1 or >= 0.3.0, <= 0.3.0 or >= 0.4.0, <= 0.4.0 or >= 0.4.1, <= 0.4.1 or >= 0.4.2, <= 0.4.2 or >= 0.4.3, <= 0.4.3 or >= 0.4.4, <= 0.4.4 or >= 0.4.5, <= 0.4.5 or >= 0.5.0, <= 0.5.0 or >= 0.6.0, <= 0.6.0 or >= 0.6.1, <= 0.6.1 or >= 0.7.0, <= 0.7.0 or >= 0.7.1, <= 0.7.1 or >= 0.8.0, <= 0.8.0 or >= 0.8.1, <= 0.8.1 or >= 0.8.2, <= 0.8.2 or >= 0.8.3, <= 0.8.3 or >= 0.8.4, <= 0.8.4 or >= 0.9.0, <= 0.9.0 or >= 0.9.1, <= 0.9.1 or < 0.19.1 or >= 0.0.1, <= 0.0.1 or >= 0.1.1, <= 0.1.1 or >= 0.1.2, <= 0.1.2 or >= 0.1.3, <= 0.1.3 or >= 0.1.4, <= 0.1.4 or >= 0.10.0, <= 0.10.0 or >= 0.10.1, <= 0.10.1 or >= 0.10.2, <= 0.10.2 or >= 0.11.0, <= 0.11.0 or >= 0.11.1, <= 0.11.1 or >= 0.12.0, <= 0.12.0 or >= 0.12.1, <= 0.12.1 or >= 0.12.2, <= 0.12.2 or >= 0.12.3, <= 0.12.3 or >= 0.13.0, <= 0.13.0 or >= 0.13.1, <= 0.13.1 or >= 0.14.0, <= 0.14.0 or >= 0.14.1, <= 0.14.1 or >= 0.14.2, <= 0.14.2 or >= 0.15.0, <= 0.15.0 or >= 0.16.0, <= 0.16.0 or >= 0.16.1, <= 0.16.1 or >= 0.16.2, <= 0.16.2 or >= 0.16.3, <= 0.16.3 or >= 0.16.4, <= 0.16.4 or >= 0.16.5, <= 0.16.5 or >= 0.16.6, <= 0.16.6 or >= 0.17.0, <= 0.17.0 or >= 0.17.1, <= 0.17.1 or >= 0.17.2, <= 0.17.2 or >= 0.17.3, <= 0.17.3 or >= 0.18.0, <= 0.18.0 or >= 0.18.1, <= 0.18.1 or >= 0.19.0, <= 0.19.0 or >= 0.2.0, <= 0.2.0 or >= 0.2.1, <= 0.2.1 or >= 0.3.0, <= 0.3.0 or >= 0.4.0, <= 0.4.0 or >= 0.4.1, <= 0.4.1 or >= 0.4.2, <= 0.4.2 or >= 0.4.3, <= 0.4.3 or >= 0.4.4, <= 0.4.4 or >= 0.4.5, <= 0.4.5 or >= 0.5.0, <= 0.5.0 or >= 0.6.0, <= 0.6.0 or >= 0.6.1, <= 0.6.1 or >= 0.7.0, <= 0.7.0 or >= 0.7.1, <= 0.7.1 or >= 0.8.0, <= 0.8.0 or >= 0.8.1, <= 0.8.1 or >= 0.8.2, <= 0.8.2 or >= 0.8.3, <= 0.8.3 or >= 0.8.4, <= 0.8.4 or >= 0.9.0, <= 0.9.0 or >= 0.9.1, <= 0.9.1
Patched version
Not yet available
GHSA-RXW2-PC8J-VXWM

An early warning has been issued regarding a vulnerability in the fast-mcp-telegram package that allows path traversal to bypass Telegram session protection. Users of affected versions should take immediate action.

What happened

An early warning has been issued for a vulnerability in the fast-mcp-telegram package. The package reportedly validates HTTP Bearer tokens by joining the raw token string into a session-file path, which allows path traversal to bypass reserved Telegram session protection. This means an unauthenticated network client can access the Telegram account represented by the default `telegram.session` file without knowing a generated bearer token.

The vulnerability affects versions of fast-mcp-telegram less than 0.19.1 and various other specified version ranges as detailed in the threat data. The issue is under investigation and no exploitation in the wild has been confirmed yet.

What to do about it

How 0Day would have caught this

MATCHED TO YOUR ACTUAL DEPENDENCY GRAPH0Day matches every incoming threat signal against your GitHub organization’s full dependency graph, including transitive dependencies. If fast-mcp-telegram is anywhere in your dependency tree, the engineers who own the affected repositories get a push alert the moment it is flagged — no manual audit to remember to run.

Read how this differs from waiting on a scanner to catch a known advisory, or see the exact, read-only access 0Day needs to do this for an organization.

Frequently asked questions

Am I affected?

You are affected if you are using a version of fast-mcp-telegram less than 0.19.1 or within the specified vulnerable version ranges.

What should I do right now?

Monitor the primary sources for updates on a fixed version and rotate any affected session tokens immediately.

Is there a fixed version available?

No official fix has been published yet. Continue to monitor the primary sources for updates.

Sources

Join the 0Day waitlist →

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