Описание
RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23, Incomplete fix for CVE-2026-44838: escaperegexchar/1 does not escape -, leaving room for an MQTT topic permission bypass. the CVE-2026-44838 fix made expandtopicpermission/2 escape regex metacharacters in expanded topic-permission variables (escaperegex(V)), but escaperegexchar/1 escapes \ ^ $ . | ? + ( ) [ ] { } and omits -. When a topic permission template places {clientid} inside a [...] character class A low-privileged authenticated MQTT user controlling its clientid can broaden topic authorization (read and write) when templates embed {clientid} in a [...] This issue is fixed in versions 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23.
A flaw was found in rabbitmq-server. Due to improper regular expression character escaping, topic permission templates for Message Queuing Telemetry Transport (MQTT) clients fail to sanitize hyphen characters. An authenticated, low-privileged attacker controlling their client identifier can exploit this flaw to alter permission evaluation rules. This issue allows the attacker to bypass authorization controls and gain unauthorized read and write access to restricted messaging topics.
Отчет
This vulnerability is classified as Moderate severity rather than Important because successful exploitation requires valid client credentials and relies on an uncommon configuration where topic permission templates embed client identifiers inside bracketed regular expression character classes. Red Hat products typically deploy RabbitMQ for internal system communication over AMQP with the MQTT plugin disabled by default. Environments that do not use MQTT topic authorization rules incorporating character classes remain unaffected.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Hardened Images | rabbitmq-server4.2 | Will not fix | ||
| Red Hat OpenStack Platform 13 (Queens) | rabbitmq-server | Out of support scope | ||
| Red Hat OpenStack Platform 16.2 | rabbitmq-server | Out of support scope | ||
| Red Hat OpenStack Platform 17.1 | rabbitmq-server | Out of support scope | ||
| Red Hat OpenStack Platform 18.0 | rabbitmq-server | Fix deferred | ||
| Red Hat Hardened Images | rabbitmq-server4-3-main-4.3.6-1.hum1 | Fixed | RHSA-2026:67552 | 15.09.2026 |
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Дополнительная информация
Статус:
EPSS
4.2 Medium
CVSS3
Связанные уязвимости
RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23, Incomplete fix for CVE-2026-44838: escaperegexchar/1 does not escape -, leaving room for an MQTT topic permission bypass. the CVE-2026-44838 fix made expandtopicpermission/2 escape regex metacharacters in expanded topic-permission variables (escaperegex(V)), but escaperegexchar/1 escapes \ ^ $ . | ? + ( ) [ ] { } and omits -. When a topic permission template places {clientid} inside a [...] character class A low-privileged authenticated MQTT user controlling its clientid can broaden topic authorization (read and write) when templates embed {clientid} in a [...] This issue is fixed in versions 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23.
RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23, Incomplete fix for CVE-2026-44838: escaperegexchar/1 does not escape -, leaving room for an MQTT topic permission bypass. the CVE-2026-44838 fix made expandtopicpermission/2 escape regex metacharacters in expanded topic-permission variables (escaperegex(V)), but escaperegexchar/1 escapes \ ^ $ . | ? + ( ) [ ] { } and omits -. When a topic permission template places {clientid} inside a [...] character class A low-privileged authenticated MQTT user controlling its clientid can broaden topic authorization (read and write) when templates embed {clientid} in a [...] This issue is fixed in versions 4.3.3 and 4.2.9 and 4.1.14 and 4.0.23.
RabbitMQ: Incomplete fix for CVE-2026-44838: `escape_regex_char/1` does not escape `-`, leaving room for an MQTT topic permission bypass
RabbitMQ is a messaging and streaming broker. From 4.0.0 until 4.3.3 a ...
EPSS
4.2 Medium
CVSS3