CVE-2021-3734Network attack vector

Administrator interaction manipulation via frameable interface

Published Aug 26, 2021 · Updated Aug 3, 2024

Clickjacking in YOURLS 1.8.1 and earlier allows remote attackers to manipulate administrator interactions through a framed admin interface. The admin HTML and AJAX paths omit an anti-framing response header, so an external site can embed the interface and overlay deceptive controls. An authenticated administrator must interact with attacker-controlled content; published sources do not identify the specific actions exposed.

CVSS severity6.5
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Clickjacking in YOURLS 1.8.1 and earlier allows remote attackers to manipulate administrator interactions through a framed admin interface. The admin HTML and AJAX paths omit an anti-framing response header, so an external site can embed the interface and overlay deceptive controls. An authenticated administrator must interact with attacker-controlled content; published sources do not identify the specific actions exposed.

The record

CVE
CVE-2021-3734
Published
Aug 26, 2021
Updated
Aug 3, 2024
Vendor
YOURLS
Product
YOURLS
Classifications
CWE-1021, CWE-352
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 26, 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

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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=unspecified <=1.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

YOURLS · YOURLSversion=unspecified <=1.8.1

Published CVSS scores

8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
6.5Protect AICVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/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.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-1021Improper Restriction of Rendered UI Layers or Frames
CWE-352Cross-Site Request Forgery (CSRF)

Public exploit references

No public exploit references are available in this record.

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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