CVE-2021-24638Public exploitNetwork attack vector

Unauthenticated CSS overwrite via REST path traversal

Published Sep 20, 2021 · Updated Aug 3, 2024

Path traversal in OMGF before 4.5.4 allows remote attackers to overwrite arbitrary CSS files through an unauthenticated REST request. The download endpoint uses the unescaped, unvalidated handle parameter as a filesystem path while fetching Google Fonts CSS and font files. No account or user interaction is required; a crafted handle can escape the intended directory and replace a chosen CSS file or populate an existing directory with downloaded fonts.

CVSS severity9.1
Critical
EPSS probability1.82%
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

Path traversal in OMGF before 4.5.4 allows remote attackers to overwrite arbitrary CSS files through an unauthenticated REST request. The download endpoint uses the unescaped, unvalidated handle parameter as a filesystem path while fetching Google Fonts CSS and font files. No account or user interaction is required; a crafted handle can escape the intended directory and replace a chosen CSS file or populate an existing directory with downloaded fonts.

The record

CVE
CVE-2021-24638
Published
Sep 20, 2021
Updated
Aug 3, 2024
Vendor
Daan van den Bergh
Product
OMGF
Classifications
CWE-22, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record 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=4.5.4 <4.5.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Daan van den Bergh · OMGFversion=4.5.4 <4.5.4

Published CVSS scores

6.4NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:P
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
T1190Exploit Public-Facing Application

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