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, a malicious client which can connect to the WebSockets port can cause unbounded memory use in the nats-server before authentication; this requires sending a corresponding amount of data. This is a milder variant of CVE-2026-27571. That earlier issue was a compression bomb, this vulnerability is not. Attacks against this new issue thus require significant client bandwidth. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable websockets if not required for project deployment.
CVE-2026-33219
This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). 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).
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.3
- EG Score
- 5.3(low)
- EPSS
- 41.1%
- KEV
- Not listed
Published
March 25, 2026
Last Modified
June 30, 2026
References (10)
- security-advisories@githubhttps://advisories.nats.io/CVE/secnote-2026-02.txt
- security-advisories@githubhttps://advisories.nats.io/CVE/secnote-2026-11.txt
- security-advisories@githubhttps://github.com/advisories/GHSA-qrvq-68c2-7grw
- security-advisories@githubhttps://github.com/nats-io/nats-server/security/advisories/GHSA-8r68-gvr4-jh7j
- 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-2026-33219
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://bugzilla.redhat.com/show_bug.cgi?id=2451445
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46chttps://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33219.json
Vendor Advisories for CVE-2026-33219(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(1)
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
Frequently asked(5)
What is CVE-2026-33219?
When was CVE-2026-33219 disclosed?
Is CVE-2026-33219 actively exploited?
What is the CVSS score of CVE-2026-33219?
How do I remediate CVE-2026-33219?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-33219
Is Your Infrastructure Affected by CVE-2026-33219?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.