GHSA-55h8-8g96-x4hjPublished

NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers

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cve-program · CVE-2026-33246

Published

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. The nats-server offers a `Nats-Request-Info:` message header, providing information about a request. This is supposed to provide enough information to allow for account/user identification, such that NATS clients could make their own decisions on how to trust a message, provided that they trust the nats-server as a broker. A leafnode connecting to a nats-server is not fully trusted unless the system account is bridged too. Thus identity claims should not have propagated unchecked. Prior to versions 2.11.15 and 2.12.6, NATS clients relying upon the Nats-Request-Info: header could be spoofed. This does not directly affect the nats-server itself, but the CVSS Confidentiality and Integrity scores are based upon what a hypothetical client might choose to do with this NATS header. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

Source published: 25 Mar 2026 19:50:03 UTC
Source modified: 28 Mar 2026 01:42:55 UTC
Saved here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

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CVSS 3.1 · 6.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

euvd · EUVD-2026-15973

Published

Additional publisher context

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Mar 25, 2026, 7:50:03 PM

dateUpdated: Mar 28, 2026, 1:42:55 AM

1 related source bulletins · separate from aliases

WID-SEC-W-2026-0858: NATS Server: Mehrere Schwachstellen

CVE-2026-33215 · CVE-2026-33216 · CVE-2026-33217 · CVE-2026-33218 · CVE-2026-33219 · CVE-2026-33222 · CVE-2026-33223 · CVE-2026-33246 · CVE-2026-33247 · CVE-2026-33248 · CVE-2026-33249

Source published: Mar 25, 2026, 7:50:03 PM (timezone not stated)
Source modified: Mar 28, 2026, 1:42:55 AM (timezone not stated)
Saved here: 15 Nov 2026 10:02:40 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 3.1 · 6.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

nvd · CVE-2026-33246

Published

Additional publisher context

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Analyzed

Weakness classifications: CWE-287 · CWE-290

Original publisher date fields

published: 2026-03-25T20:16:33.010

lastModified: 2026-06-17T10:37:11.157

1 source CPE criteria · context only

cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*

The original JSON retains the logical configuration operators, exclusions and version bounds.

Source published: 25 Mar 2026 20:16:33 UTC
Source modified: 17 Jun 2026 10:37:11 UTC
Saved here: 25 Oct 2026 08:17:18 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 6.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

CVSS 3.1 · [email protected] · Primary · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N

osv · GHSA-55h8-8g96-x4hj

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 allows hub/spoke topologies using "leafnode" connections by other nats-servers. NATS messages can have headers. ### Problem Description The nats-server offers a `Nats-Request-Info:` message header, providing information about a request. This is supposed to provide enough information to allow for account/user identification, such that NATS clients could make their own decisions on how to trust a message, provided that they trust the nats-server as a broker. A leafnode connecting to a nats-server is not fully trusted unless the system account is bridged too. Thus identity claims should not have propagated unchecked. Thus NATS clients relying upon the Nats-Request-Info: header could be spoofed. Does not directly affect the nats-server itself, but the CVSS Confidentiality and Integrity scores are based upon what a hypothetical client might choose to do with this NATS header. ### Affected Versions Any version before v2.12.6 or v2.11.15 ### Workarounds None.

Source published: 24 Mar 2026 21:50:25 UTC
Source modified: 10 Sep 2026 03:50:59 UTC
Saved here: 24 Oct 2026 13:19:41 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

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Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:N

Publisher rating · MODERATE

osv · GO-2026-4830

Published

NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers in github.com/nats-io/nats-server

Source published: 26 Mar 2026 20:33:05 UTC
Source modified: 27 Mar 2026 18:26:07 UTC
Saved here: 24 Oct 2026 13:19:41 UTC
Source terms: OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

Source: osv · OSV · upstream source license applies. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.