CVE-2020-12137

Name: CVE-2020-12137
Creator: NVD / NIST
Published: 2020-04-24T13:15:11.78+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 2.29%

Last modified Jun 17, 2026

CVE-2020-12137 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. 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.. EPSS estimates a 2.29% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

2.29%

81.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-79

Affected Software

Vendor	Product	Versions	Update
Gnu	Mailman	>= 2.0, < 2.1.30	—
Debian	Debian Linux	9.0	—
Debian	Debian Linux	10.0	—
Fedoraproject	Fedora	31	—
Fedoraproject	Fedora	32	—
Debian	Debian Linux	8.0	—
Canonical	Ubuntu Linux	16.04	—
Canonical	Ubuntu Linux	18.04	—
Opensuse	Backports Sle	15.0	Sp2
Opensuse	Leap	15.2	—

References

http://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/NEWSThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00047.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00063.htmlMailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2020/04/24/3Mailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/05/msg00002.htmlMailing List, Third Party Advisory
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/Third Party Advisory
https://www.debian.org/security/2020/dsa-4664Third Party Advisory
https://www.openwall.com/lists/oss-security/2020/02/24/2Mailing List, Third Party Advisory
https://www.openwall.com/lists/oss-security/2020/02/24/3Mailing List, Third Party Advisory
http://bazaar.launchpad.net/~mailman-coders/mailman/2.1/view/head:/NEWSThird Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00047.htmlMailing List, Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00063.htmlMailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2020/04/24/3Mailing List, Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/05/msg00002.htmlMailing List, Third Party Advisory
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/Third Party Advisory
https://www.debian.org/security/2020/dsa-4664Third Party Advisory
https://www.openwall.com/lists/oss-security/2020/02/24/2Mailing List, Third Party Advisory
https://www.openwall.com/lists/oss-security/2020/02/24/3Mailing List, Third Party Advisory

Timeline

Published: Apr 24, 2020
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2020-12137?

How severe is CVE-2020-12137?

CVE-2020-12137 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 2.29% probability of exploitation in the next 30 days.

How do I fix CVE-2020-12137?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2020-12137?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST