CVE-2021-3181

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in, but needs a user to act. High risk of service disruption.

Exploit odds

2.8% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2021-01-19 15:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 04:04 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 2.8% in the next 30 days (EPSS).
• Severity: 6.5 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2021-01-19 15:15 UTC

Last modified

2026-06-17 04:04 UTC

Exploit probability

2.8% · EPSS, next 30 days

Weakness

CWE-401

Record status

Modified

Affected

• Mutt ≤ 2.0.4
• Debian Linux 9.0
• Debian Linux 10.0
• Fedoraproject Fedora 32
• Fedoraproject Fedora 33

Attack profile CVSS 3.1 · 6.5

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-3181.md and follow it. Check whether this project is affected by CVE-2021-3181. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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