CVE-2020-21142Public exploitNetwork attack vector

Stored XSS via unescaped mail server input

Published Jun 28, 2021 · Updated Aug 4, 2024

Stored XSS in IPFire 2.23 allows remote attackers to execute script in an administrator's browser through crafted Mail Service input. The mail.cgi validation path appends invalid mail-server and port values directly to an HTML error message without escaping them. The Mail Service page must be enabled and a victim must render the error; the script can issue a same-origin Wake-on-LAN request that bypasses the Referer-based CSRF check.

CVSS severity6.1
Medium
EPSS probability0.69%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in IPFire 2.23 allows remote attackers to execute script in an administrator's browser through crafted Mail Service input. The mail.cgi validation path appends invalid mail-server and port values directly to an HTML error message without escaping them. The Mail Service page must be enabled and a victim must render the error; the script can issue a same-origin Wake-on-LAN request that bypasses the Referer-based CSRF check.

The record

CVE
CVE-2020-21142
Published
Jun 28, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-79
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 28, 2021CVE 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

6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/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 exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

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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