CVE-2021-3181

Name: CVE-2021-3181
Creator: NVD / NIST
Published: 2021-01-19T15:15:12.327+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 2.80%

Last modified Jun 17, 2026

CVE-2021-3181 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. rfc822.c in Mutt through 2.0.4 allows remote attackers to cause a denial of service (mailbox unavailability) by sending email messages with sequences of semicolon characters in RFC822 address fields (aka terminators of empty groups). A small email message from the attacker can cause large memory consumption, and the victim may then be unable to see email messages from other persons.. EPSS estimates a 2.80% chance of exploitation in the next 30 days.

Description

rfc822.c in Mutt through 2.0.4 allows remote attackers to cause a denial of service (mailbox unavailability) by sending email messages with sequences of semicolon characters in RFC822 address fields (aka terminators of empty groups). A small email message from the attacker can cause large memory consumption, and the victim may then be unable to see email messages from other persons.

Metrics

CVSS 3.1

6.5/10

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

EPSS Probability

2.80%

84.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-401

Affected Software

Vendor	Product	Versions
Mutt	Mutt	<= 2.0.4
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Fedoraproject	Fedora	32
Fedoraproject	Fedora	33

References

http://www.openwall.com/lists/oss-security/2021/01/19/10Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/01/27/3Mailing List, Third Party Advisory
https://gitlab.com/muttmua/mutt/-/commit/4a2becbdb4422aaffe3ce314991b9d670b7adf17Patch, Third Party Advisory
https://gitlab.com/muttmua/mutt/-/commit/939b02b33ae29bc0d642570c1dcfd4b339037d19Patch, Third Party Advisory
https://gitlab.com/muttmua/mutt/-/commit/d4305208955c5cdd9fe96dfa61e7c1e14e176a14Patch, Third Party Advisory
https://gitlab.com/muttmua/mutt/-/issues/323Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/01/msg00017.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DXGWXFO77HBCD3VYEIYHHYU33LYWWWNQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/P2OMLQKAOHPYQA4GI7ZUO6UKCPUHLYO7/
https://security.gentoo.org/glsa/202101-25Third Party Advisory
https://www.debian.org/security/2021/dsa-4838Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/01/19/10Mailing List, Third Party Advisory
http://www.openwall.com/lists/oss-security/2021/01/27/3Mailing List, Third Party Advisory
https://gitlab.com/muttmua/mutt/-/commit/4a2becbdb4422aaffe3ce314991b9d670b7adf17Patch, Third Party Advisory
https://gitlab.com/muttmua/mutt/-/commit/939b02b33ae29bc0d642570c1dcfd4b339037d19Patch, Third Party Advisory
https://gitlab.com/muttmua/mutt/-/commit/d4305208955c5cdd9fe96dfa61e7c1e14e176a14Patch, Third Party Advisory
https://gitlab.com/muttmua/mutt/-/issues/323Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/01/msg00017.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/DXGWXFO77HBCD3VYEIYHHYU33LYWWWNQ/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/P2OMLQKAOHPYQA4GI7ZUO6UKCPUHLYO7/
https://security.gentoo.org/glsa/202101-25Third Party Advisory
https://www.debian.org/security/2021/dsa-4838Third Party Advisory

Timeline

Published: Jan 19, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-3181?

How severe is CVE-2021-3181?

CVE-2021-3181 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 2.80% probability of exploitation in the next 30 days.

How do I fix CVE-2021-3181?

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-2021-3181?

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

Scan your code now

Source: NVD / NIST