CVE-2021-38354Network attack vector

Script execution via unencoded gm_error reflection

Published Sep 10, 2021 · Updated May 2, 2025

Reflected XSS in GNU-Mailman Integration 1.0.6 and earlier allows remote attackers to execute scripts via a crafted gm_error parameter. The plugin's includes/admin/mailing-lists-page.php page places gm_error request data into an administrative error response without output encoding. Exploitation requires a user to follow a crafted request and executes attacker-controlled script in the site's browser origin, enabling access to or modification of data available to that session.

CVSS severity6.1
Medium
EPSS probability0.90%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in GNU-Mailman Integration 1.0.6 and earlier allows remote attackers to execute scripts via a crafted gm_error parameter. The plugin's includes/admin/mailing-lists-page.php page places gm_error request data into an administrative error response without output encoding. Exploitation requires a user to follow a crafted request and executes attacker-controlled script in the site's browser origin, enabling access to or modification of data available to that session.

The record

CVE
CVE-2021-38354
Published
Sep 10, 2021
Updated
May 2, 2025
Vendor
GNU Mailman
Product
Mailman
Classifications
CWE-79, CAPEC-591, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 10, 2021CVE publishedPublication date reported by the CVE source.
  2. May 2, 2025Record 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=1.0.6 <=1.0.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

GNU Mailman · Mailmanversion=1.0.6 <=1.0.6

Published CVSS scores

6.1WordfenceCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CAPEC-591Reflected XSS
T1189Drive-by Compromise

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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