Описание
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 the memory limit of the process and terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No publicly available exploits are known.
A flaw was found in dovecot. A remote attacker can craft a malicious email with an excessive number of email addresses or MIME parameters in its headers. When a user attempts to read this message over IMAP, the parsing process consumes an inordinate amount of memory, leading to the termination of the process. This can result in a denial of service for the affected user.
Отчет
This vulnerability is rated as an Important severity flaw because an unauthenticated remote sender can deliver specially crafted messages that trigger denial of service conditions without requiring privileges on the mail server. In typical Red Hat Enterprise Linux deployments running Dovecot as an IMAP service, processing messages containing bloated header fields exhausts process memory limits during user retrieval sessions, abruptly terminating worker processes. While process isolation confines crashes to individual user sessions and prevents broader host compromise, repeated delivery can persistently disrupt mailbox availability.
Меры по смягчению последствий
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | dovecot | Out of support scope | ||
| Red Hat Enterprise Linux 7 | dovecot | Affected | ||
| Red Hat Enterprise Linux 10 | dovecot | Fixed | RHSA-2026:79371 | 08.10.2026 |
| Red Hat Enterprise Linux 8 | dovecot | Fixed | RHSA-2026:76763 | 06.10.2026 |
| Red Hat Enterprise Linux 9 | dovecot | Fixed | RHSA-2026:80825 | 12.10.2026 |
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Дополнительная информация
Статус:
EPSS
7.5 High
CVSS3
Связанные уязвимости
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 the memory limit of the process and terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No publicly available exploits are known.
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 the memory limit of the process and terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No publicly available exploits are known.
An attacker that can send mail to a user can craft a message whose hea ...
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 the memory limit of the process and terminate it, causing denial of service for the affected user. Update to non-vulnerable version. No publicly available exploits are known.
EPSS
7.5 High
CVSS3