CVE-2021-47208Public exploitNetwork attack vector

Service interruption via unrestricted route format detection

Published Apr 7, 2024 · Updated Mar 20, 2025

Uncontrolled resource consumption in Mojolicious before 9.11 allows remote authenticated users to interrupt service via crafted route suffixes. Mojolicious::Routes::Pattern enables automatic format detection by default and captures unrestricted file-extension text into the format stash, driving invalid template resolution. Applications with reachable routes that accept automatic formats are exposed; repeated crafted requests consume server resources and interrupt request handling.

CVSS severity4.3
Medium
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Uncontrolled resource consumption in Mojolicious before 9.11 allows remote authenticated users to interrupt service via crafted route suffixes. Mojolicious::Routes::Pattern enables automatic format detection by default and captures unrestricted file-extension text into the format stash, driving invalid template resolution. Applications with reachable routes that accept automatic formats are exposed; repeated crafted requests consume server resources and interrupt request handling.

The record

CVE
CVE-2021-47208
Published
Apr 7, 2024
Updated
Mar 20, 2025
Vendor
Mojolicious
Product
Mojolicious
Classifications
CWE-400, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 7, 2024CVE publishedPublication date reported by the CVE source.
  2. Mar 20, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <9.11

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Mojolicious · Mojoliciousversion=0 <9.11

Published CVSS scores

4.3CISA-ADPCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-400Uncontrolled Resource Consumption
T1499.004Application or System Exploitation

Public exploit references

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

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo