CVE-2021-45268Public exploitNetwork attack vector

Disputed code execution via forged add-on installation

Published Feb 3, 2022 · Updated Aug 4, 2024

Cross-site request forgery in Backdrop CMS 1.20 allows remote attackers to execute PHP code by inducing an administrator to install an add-on. The published proof of concept posts to the system/ajax installer endpoint with captured session and form tokens, directing it to fetch an archive containing shell.php. The claim is disputed because exploitation requires an entitled high-privileged user’s valid session state and interaction, privileges that already permit arbitrary add-on installation.

CVSS severity8.8
High
EPSS probability1.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in Backdrop CMS 1.20 allows remote attackers to execute PHP code by inducing an administrator to install an add-on. The published proof of concept posts to the system/ajax installer endpoint with captured session and form tokens, directing it to fetch an archive containing shell.php. The claim is disputed because exploitation requires an entitled high-privileged user’s valid session state and interaction, privileges that already permit arbitrary add-on installation.

The record

CVE
CVE-2021-45268
Published
Feb 3, 2022
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-352, T1204.001, T1505.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 3, 2022CVE 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

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

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)
T1204.001Malicious Link
T1505.003Web Shell

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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