CVE-2021-28940Public exploitNetwork attack vector

Remote code execution via injected curl options

Published Apr 2, 2021 · Updated Aug 3, 2024

Command injection in MagpieRSS 0.72 allows remote attackers to execute arbitrary commands through a crafted HTTPS RSS URL. The _httpsrequest() method in extlib/Snoopy.class.inc applies escapeshellcmd() to the URI without quoting it, so whitespace and dash-prefixed text become additional curl arguments. When either bundled script is web-accessible, no authentication is required, and curl can write web files, disclose readable local files, or contact internal services.

CVSS severity9.8
Critical
EPSS probability3.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in MagpieRSS 0.72 allows remote attackers to execute arbitrary commands through a crafted HTTPS RSS URL. The _httpsrequest() method in extlib/Snoopy.class.inc applies escapeshellcmd() to the URI without quoting it, so whitespace and dash-prefixed text become additional curl arguments. When either bundled script is web-accessible, no authentication is required, and curl can write web files, disclose readable local files, or contact internal services.

The record

CVE
CVE-2021-28940
Published
Apr 2, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-116, T1059.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 2, 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?

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

9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P

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-116Improper Encoding or Escaping of Output
T1059.004Unix 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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