CVE-2021-41250Public exploitNetwork attack vector

Moderation bypass via URL-triggered token-filter exit

Published Nov 5, 2021 · Updated Aug 4, 2024

Improper input validation in Python Discord Python Utility Bot allows remote authenticated users to bypass moderation token filters. The _has_watch_regex_match function returns before checking blocked token patterns whenever its input contains any URL, including a non-blacklisted URL. Discord server member access is sufficient to submit a mixed URL-and-token message, causing prohibited content to escape the bot's moderation response.

CVSS severity4.3
Medium
EPSS probability0.76%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Python Discord Python Utility Bot allows remote authenticated users to bypass moderation token filters. The _has_watch_regex_match function returns before checking blocked token patterns whenever its input contains any URL, including a non-blacklisted URL. Discord server member access is sufficient to submit a mixed URL-and-token message, causing prohibited content to escape the bot's moderation response.

The record

CVE
CVE-2021-41250
Published
Nov 5, 2021
Updated
Aug 4, 2024
Vendor
Python Discord
Product
Python Utility Bot
Classifications
CWE-20
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Nov 5, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 67390298852513d13e0213870e50fb3cff1424e0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Python Discord · Python Utility Botversion=< 67390298852513d13e0213870e50fb3cff1424e0

Published CVSS scores

4.0NVDAV:N/AC:L/Au:S/C:N/I:P/A:N
4.3GitHubCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-20Improper Input Validation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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