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, when using ACLs on message subjects, these ACLs were not applied in the $MQTT.> namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.
CVE-2026-33217
MEDIUMNVD 6.56.5
EchelonGraph scoreLOW confidence
This medium-severity CVE scores 6.5 under NVD CVSS v3. EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
Triggered by: NVD CVSS baseline
Sources: nvd
6.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
- Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 6.5Exploit: NoneExposed: 0
A fix is available — apply it.
- CVSS v3
- 6.5
- EG Score
- 6.5(low)
- EPSS
- 17.3%
- KEV
- Not listed
Published
March 25, 2026
Last Modified
June 30, 2026
References (8)
- security-advisories@githubhttps://advisories.nats.io/CVE/secnote-2026-07.txt
- security-advisories@githubhttps://github.com/nats-io/nats-server/security/advisories/GHSA-jxxm-27vp-c3m5
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/errata/RHSA-2026:21769
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/errata/RHSA-2026:22347
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/errata/RHSA-2026:23345
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://access.redhat.com/security/cve/CVE-2026-33217
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://bugzilla.redhat.com/show_bug.cgi?id=2451446
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33217.json
Vendor Advisories for CVE-2026-33217(3)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:23345Red Hat Product SecurityHigh
Red Hat Security Advisory: Multicluster Global Hub 1.6.2 security update
- RHSA-2026:22347Red Hat Product SecurityHigh
Red Hat Security Advisory: Multicluster Global Hub 1.4.5 security update
- RHSA-2026:21769Red Hat Product SecurityHigh
Red Hat Security Advisory: Multicluster Global Hub 1.5.4 security update
Patch Availability(3)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| redhat | multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1780167118 | 2026-06-04 | redhat |
| redhat | multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1779579439 | 2026-06-01 | redhat |
| redhat | multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1778867753 | 2026-05-28 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(2 across 1 ecosystem)
Go(2)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| github.com/nats-io/nats-server | — | — | — |
| github.com/nats-io/nats-server/v2 | — | 2.11.15 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 8× in last 7d / 11× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 16:27 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-06 02:23 UTCEPSS rescore
- 2026-07-05 02:30 UTCEPSS rescore
- 2026-07-04 06:31 UTCEPSS rescore
- 2026-07-01 15:06 UTCEPSS rescore
- 2026-06-30 23:22 UTCEPSS rescore
- 2026-06-30 04:37 UTCEG score recompute
- 2026-06-30 04:37 UTCVendor advisory
- 2026-06-30 04:32 UTCNVD updatefirst tracked
Related CVEs(same vendor + same CWE)
Same vendor
10 shownredhat
Same CWE
10 shownCWE-863 · CWE-425
Frequently asked(5)
What is CVE-2026-33217?
CVE-2026-33217 is a medium vulnerability published on March 25, 2026. 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, when using ACLs on message subjects, these ACLs were not applied in the $MQTT.> namespace, allowing MQTT clients to bypass ACL checks for MQTT subjects. Versions…
When was CVE-2026-33217 disclosed?
CVE-2026-33217 was first published in the National Vulnerability Database on March 25, 2026, with the most recent update on June 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33217 actively exploited?
CVE-2026-33217 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 17.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-33217?
CVE-2026-33217 has a CVSS v3 base score of 6.5 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-33217?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33217, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-33217
Is Your Infrastructure Affected by CVE-2026-33217?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.