CVE-2021-3181

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 2.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-01-19 · updated 2026-06-17
Weakness: CWE-401

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.

Affected products

Debian Linux: 9.0, 10.0
Fedoraproject Fedora: 32, 33
mutt: through 2.0.4

References

http://www.openwall.com/lists/oss-security/2021/01/19/10
http://www.openwall.com/lists/oss-security/2021/01/27/3
https://gitlab.com/muttmua/mutt/-/commit/4a2becbdb4422aaffe3ce314991b9d670b7adf17
https://gitlab.com/muttmua/mutt/-/commit/939b02b33ae29bc0d642570c1dcfd4b339037d19
https://gitlab.com/muttmua/mutt/-/commit/d4305208955c5cdd9fe96dfa61e7c1e14e176a14
https://gitlab.com/muttmua/mutt/-/issues/323
https://lists.debian.org/debian-lts-announce/2021/01/msg00017.html
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/202101-25
https://www.debian.org/security/2021/dsa-4838
http://www.openwall.com/lists/oss-security/2021/01/19/10

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