GHSA-pwx7-fx9r-hr4h BIT-nats-2026-33223 CVE-2026-33223 GO-2026-4835
NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing
- Severity
- 6.4 / 10
- Medium · CVSS 3.1
- Exploit chance (EPSS)
- 0.21%
- Chance of exploitation in the next 30 days. Higher than 11.89% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-290 Authentication Bypass by Spoofing
- Fix
2.11.15- Upgrade github.com/nats-io/nats-server/v2 to this version or later
Description
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.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/nats-io/nats-server | all versions |
No fix yet |
| github.com/nats-io/nats-server/v2 | < 2.11.15 |
2.11.15 |
| github.com/nats-io/nats-server/v2 | >= 2.12.0-RC.1, < 2.12.6 |
2.12.6 |
| github.com/nats-io/nats-server/v2 | < 2.11.15>= 2.12.0-RC.1, < 2.12.6 |
2.11.152.12.6 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/nats-io/nats-server/v2 Go → 2.11.15
- go
go get github.com/nats-io/nats-server/v2@v2.11.15 && go mod tidy
Severity breakdown
CVSS 3.1 6.4
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Weakness
CWE-290: Authentication Bypass by Spoofing
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-pq2q-rcw4-3hr6 NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead | High | Also affects github.com/nats-io/nats-server |
| GHSA-3f24-pcvm-5jqc NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-55h8-8g96-x4hj NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-9983-vrx2-fg9c NATS JetStream has an authorization bypass through its Management API | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-8r68-gvr4-jh7j NATS is vulnerable to pre-auth DoS through WebSockets client service | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-vprv-35vv-q339 NATS has pre-auth server panic via leafnode handling | High | Also affects github.com/nats-io/nats-server |
| GHSA-jxxm-27vp-c3m5 NATS allows MQTT clients to bypass ACL checks | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-v722-jcv5-w7mc NATS has MQTT plaintext password disclosure | High | Also affects github.com/nats-io/nats-server |
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