What’s Vulnerable › Vulnerabilities

CVE-2020-12137

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-04-24 · updated 2026-06-17
• Weakness: CWE-79

Description

GNU Mailman 2.x before 2.1.30 uses the .obj extension for scrubbed application/octet-stream MIME parts. This behavior may contribute to XSS attacks against list-archive visitors, because an HTTP reply from an archive web server may lack a MIME type, and a web browser may perform MIME sniffing, conclude that the MIME type should have been text/html, and execute JavaScript code.

Affected products

• Canonical Ubuntu Linux: 16.04, 18.04
• Debian Linux: 9.0, 10.0, 8.0
• Fedoraproject Fedora: 31, 32
• GNU Mailman: from 2.0 before 2.1.30 — fixed in 2.1.30
• openSUSE Backports Sle: 15.0-sp2
• openSUSE Leap: 15.2

How to fix

Upgrade to a fixed version: GNU Mailman 2.1.30. Check the vendor advisory for mitigations.

References

• http://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/NEWS
• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00047.html
• http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00063.html
• http://www.openwall.com/lists/oss-security/2020/04/24/3
• https://lists.debian.org/debian-lts-announce/2020/05/msg00002.html
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6YCMGTTOXXCVM4O6CYZLTZDX6YLYORNF/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/G4COSBBEMJYLV7WSW5QTUJUOFJFK47KK/
• https://usn.ubuntu.com/4348-1/
• https://www.debian.org/security/2020/dsa-4664
• https://www.openwall.com/lists/oss-security/2020/02/24/2
• https://www.openwall.com/lists/oss-security/2020/02/24/3
• http://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/NEWS

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