Bug 2451485 (CVE-2026-33249)

Summary:	CVE-2026-33249 github.com/nats-io/nats-server: NATS-Server: Unauthorized trace message redirection via message tracing headers
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	alcohan, gparvin, jbalunas, pahickey, rhaigner
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in NATS-Server. A valid client can exploit this flaw by manipulating message tracing headers to redirect trace messages to any valid subject, even those for which the client lacks publish permissions. This allows for unauthorized sending of trace messages, potentially bypassing intended access controls and leading to information misdirection within the NATS.io messaging system.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2451504
Bug Blocks:

Description OSIDB Bzimport 2026-03-25 21:02:21 UTC

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.11.0 and prior to versions 2.11.15 and 2.12.6, a valid client which uses message tracing headers can indicate that the trace messages can be sent to an arbitrary valid subject, including those to which the client does not have publish permission. The payload is a valid trace message and not chosen by the attacker. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.