Описание
Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.
A flaw was found in dovecot. An unauthenticated and remote attacker can send a specially crafted "NOOP" command containing numerous open and close parentheses without a command-ending line feed, causing the server to allocate an excessive amount of memory, resulting in a denial of service.
Отчет
This flaw allows an unauthenticated and remote attacker to cause a denial of service via a specially crafted "NOOP" command. Due to this reason, this vulnerability has been rated with an important severity.
Меры по смягчению последствий
Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | dovecot | Will not fix | ||
| Red Hat Enterprise Linux 10 | dovecot | Fixed | RHSA-2026:13498 | 04.05.2026 |
| Red Hat Enterprise Linux 10 | dovecot | Fixed | RHSA-2026:19149 | 19.05.2026 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | dovecot | Fixed | RHSA-2026:17602 | 14.05.2026 |
| Red Hat Enterprise Linux 7 Extended Lifecycle Support | dovecot | Fixed | RHSA-2026:26564 | 17.06.2026 |
| Red Hat Enterprise Linux 8 | dovecot | Fixed | RHSA-2026:13830 | 05.05.2026 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | dovecot | Fixed | RHSA-2026:19455 | 20.05.2026 |
| Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On | dovecot | Fixed | RHSA-2026:19455 | 20.05.2026 |
| Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support | dovecot | Fixed | RHSA-2026:19453 | 20.05.2026 |
| Red Hat Enterprise Linux 8.6 Telecommunications Update Service | dovecot | Fixed | RHSA-2026:19453 | 20.05.2026 |
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Дополнительная информация
Статус:
7.5 High
CVSS3
Связанные уязвимости
Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.
Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.
Sending "NOOP (((...)))" command with 4000 parenthesis open+close resu ...
Sending "NOOP (((...)))" command with 4000 parenthesis open+close results in ~1MB extra memory usage. Longer commands will result in client disconnection. This 1 MB can be left allocated for longer time periods by not sending the command ending LF. So attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Attacker could connect possibly from even a single IP and create 1000 connections to allocate 1 GB of memory, which would likely result in reaching VSZ limit and killing the process and its other proxied connections. Install fixed version, there is no other remediation. No publicly available exploits are known.
7.5 High
CVSS3