dovecot: Dovecot: Denial of Service via IMAP ID command with excessive parameters

A flaw was found in Dovecot. An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in. This action causes the server to consume excessive memory and CPU resources, leading to the termination of login processes and other active connections...

Important: dovecot

Issue Overview: An attacker that can send mail to a user can craft a message whose headers contain a very large number of email addresses or MIME parameters, which causes excessive memory usage when the message is later parsed. The message is still delivered, but reading it over IMAP can exhaust...

CVE-2026-92240

A malicious or compromised IMAP server can trigger an out-of-bounds read in the IMAP response parser by sending an untagged ' ID' response, crashing Thunderbird. The affected parsing path is reachable before authentication. This vulnerability was fixed in Thunderbird 156, Thunderbird 140.16, and...

SUSE CVE-2026-84641

A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to prefs.js. This vulnerability was fixed in Thunderbird 155, Thunderbird 140.15, and Thunderbird 153.2...

Linux Distros Unpatched Vulnerability : CVE-2026-84641

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - A malicious IMAP server can trigger use-after-free and heap-memory disclosure by sending a crafted ID response. Heap contents can ultimately be persisted to...

CVE-2026-42391

A flaw was found in Dovecot. An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in. This action causes the server to consume excessive memory and CPU resources, leading to the termination of login processes and other active connections...

SUSE CVE-2026-42391

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by...

Linux Distros Unpatched Vulnerability : CVE-2026-42391

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow...

ALPINE-CVE-2026-42391

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by...

CVE-2026-42391

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by...

AZL-98262 CVE-2026-42391 affecting package dovecot 2.3.20-1

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by...

CVE-2026-42391

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by...

CVE-2026-42391

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by...

CVE-2026-42391

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by...

CVE-2026-42391

Open-Xchange Dovecot is vulnerable to a denial-of-service attack in its imap-login process. An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before authentication, causing disproportionate memory and CPU consumption . The resulting out-of-memory termi...

EUVD-2026-67674

An unauthenticated attacker can send an IMAP ID command with a very large number of parameters before logging in, which causes memory and CPU usage to grow disproportionately. The login process can be terminated by the out-of-memory handling, which also terminates all other connections handled by...

PT-2026-83067

Name of the Vulnerable Software and Affected Versions dovecot versions prior to 2.4.5-1.1 Description An unauthenticated attacker can send an IMAP ID command containing an excessive number of parameters before authentication. This action causes disproportionate growth in memory and CPU usage,...

ImapEngine affected by command injection via the ID command parameters

Versions of the package directorytree/imapengine before 1.22.3 are vulnerable to Improper Neutralization of Special Elements in Output Used by a Downstream Component 'Injection' via the id function in ImapConnection.php due to improperly escaping user input before including it in IMAP ID commands...

PT-2026-8056

Name of the Vulnerable Software and Affected Versions directorytree/imapengine versions prior to 1.22.3 Description The software contains a flaw due to improper handling of user-supplied data before it is used in IMAP ID commands within the ImapConnection.php file. Specifically, the id function...

Fedora 26 : 1:dovecot (2017-e8b639c286)

quota: Add plugin quotamaxmailsize setting to limit the maximum individual mail size that can be saved. + imapc: Add imapcfeatures=delay-login. If set, connecting to the remote IMAP server isn't done until it's necessary. + imapc: Add imapcconnectionretrycount and imapcconnectionretryinterval...