CVE-2026-67407: 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…

PriorityP339high7.1CVSS 3.1

AVNACLPRLUINSUCHILAN

EPSS

0.23%

12.6th percentile

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.

Affected

5 ranges

Vendor	Product	Version range	Fixed in
broadcom	rabbitmq_server	>= 4.0.0 < 4.0.23	4.0.23
broadcom	rabbitmq_server	>= 4.1.0 < 4.1.14	4.1.14
broadcom	rabbitmq_server	>= 4.2.0 < 4.2.9	4.2.9
broadcom	rabbitmq_server	>= 4.3.0 < 4.3.3	4.3.3
rabbitmq	rabbitmq-server	—	—

CVSS provenance

nvdv3.17.1HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N

nvdv4.05.1MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

vendor_redhat8.1HIGH

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