Unauthorized message injection via unchecked trace destination
Published Mar 25, 2026 · Updated Mar 25, 2026
Incorrect authorization in NATS Server allows remote authenticated users to redirect trace events to subjects they cannot publish to. The server accepts the Nats-Trace-Dest header on a client message and emits a trace event without enforcing that client's publish permission on the selected destination. Exploitation requires a valid client able to send message-tracing headers; the injected payload is a server-generated trace event rather than attacker-chosen content.
Summary
What happened
Incorrect authorization in NATS Server allows remote authenticated users to redirect trace events to subjects they cannot publish to. The server accepts the Nats-Trace-Dest header on a client message and emits a trace event without enforcing that client's publish permission on the selected destination. Exploitation requires a valid client able to send message-tracing headers; the injected payload is a server-generated trace event rather than attacker-chosen content.
The record
- CVE
- CVE-2026-33249
- Published
- Mar 25, 2026
- Updated
- Mar 25, 2026
- Vendor
- NATS.io
- Product
- NATS Server
- Classifications
- CWE-863, T1565.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 25, 2026CVE publishedPublication date reported by the CVE source.
- Mar 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 2.11.0, < 2.11.15
- Affected versionversion=>= 2.12.0-preview.1, < 2.12.6
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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