CVE-2026-33223

NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing

CVSS 3.1 6.4 MEDIUMEUVD CVSS 3.1 6.4 CVSS 3.1 · [email protected] · Secondary 6.4 MEDIUMCVSS 3.1 · [email protected] · Primary 5.4 MEDIUMCVSS_V3 Publisher rating MODERATEFixed by github.com/nats-io/nats-server/v2 2.11.15 Fixed by github.com/nats-io/nats-server/v2 2.12.6osv · severity unknownFixed by github.com/nats-io/nats-server/v2 2.11.15 Fixed by github.com/nats-io/nats-server/v2 2.12.6KEV status unknown

Original advisory

cve-program · CVE-2026-33223

Published

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, the NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

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euvd · EUVD-2026-15996

Published

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nvd · CVE-2026-33223

Published

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osv · GHSA-pwx7-fx9r-hr4h

Published

### Background NATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing. The nats-server offers a `Nats-Request-Info:` message header, providing information about a request. ### Problem Description The NATS message header `Nats-Request-Info:` is supposed to be a guarantee of identity by the NATS server, but the stripping of this header from inbound messages was not fully effective. An attacker with valid credentials for any regular client interface could thus spoof their identity to services which rely upon this header. ### Affected Versions Any version before v2.12.6 or v2.11.15 ### Workarounds None.

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osv · GO-2026-4835

Published

NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing in github.com/nats-io/nats-server

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Affected versions, risk and source history

Exploitation and risk

Source status

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Risk history

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Advisory history

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13 Nov 2026 20:09:45 UTC