CVE-2026-33219

MEDIUMPre-NVD 5.35.3
EchelonGraph scoreLOW confidence

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).

Triggered by: NVD CVSS baseline
Sources: secondary
5.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 1%CVSS: 5.3Exploit: NoneExposed: 0

A fix is available — apply it.

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.

CVSS v3
5.3
EG Score
5.3(low)
EG Risk
—
EPSS
41.7%
KEV
Not listed

Published

March 25, 2026

Last Modified

July 20, 2026

Advisory Details (10)

Auto-updated Jul 19, 2026
Patch available. Sources: github, redhat.
redhat Patch Available
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33219.json
redhat

2451445 – (CVE-2026-33219) CVE-2026-33219 github.com/nats-io/nats-server: NATS-Server: Denial of Service via unbounded memory use in WebSockets

https://bugzilla.redhat.com/show_bug.cgi?id=2451445
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-33219
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:23345
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:22347
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:21769
github Patch Available

WebSockets pre-auth DoS · Advisory · nats-io/nats-server · GitHub

https://github.com/nats-io/nats-server/security/advisories/GHSA-8r68-gvr4-jh7j
github Patch Available

nats-server websockets are vulnerable to pre-auth memory DoS · CVE-2026-27571 · GitHub Advisory Database · GitHub

https://github.com/advisories/GHSA-qrvq-68c2-7grw
generic
https://advisories.nats.io/CVE/secnote-2026-11.txt
generic
https://advisories.nats.io/CVE/secnote-2026-02.txt

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.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatmulticluster-globalhub/multicluster-globalhub-grafana-rhel9:17801671182026-06-04redhat
redhatmulticluster-globalhub/multicluster-globalhub-grafana-rhel9:17795794392026-06-01redhat
redhatmulticluster-globalhub/multicluster-globalhub-grafana-rhel9:17788677532026-05-28redhat

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)
PackageVulnerable rangeFixed inDependents
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 9× in last 7d / 32× 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.

  1. 2026-07-22 14:08 UTCEPSS rescore
  2. 2026-07-21 15:24 UTCEPSS rescore
  3. 2026-07-20 17:08 UTCEPSS rescore
  4. 2026-07-19 14:31 UTCEPSS rescore
  5. 2026-07-19 02:29 UTCEPSS rescore
  6. 2026-07-18 10:04 UTCEPSS rescore
  7. 2026-07-18 06:59 UTCOSV refresh
  8. 2026-07-16 17:03 UTCEPSS rescore
  9. 2026-07-16 17:03 UTCEPSS rescore
  10. 2026-07-15 16:57 UTCEPSS rescore
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 02:00 UTCEPSS rescore
  13. 2026-07-15 02:00 UTCEPSS rescore
  14. 2026-07-13 22:30 UTCEPSS rescore
  15. 2026-07-13 06:13 UTCEPSS rescore
  16. 2026-07-13 06:13 UTCEPSS rescore
  17. 2026-07-12 05:46 UTCEPSS rescore
  18. 2026-07-11 08:27 UTCEPSS rescore
  19. 2026-07-09 19:10 UTCEPSS rescore
  20. 2026-07-08 15:15 UTCEPSS rescore
  21. 2026-07-07 13:46 UTCEPSS rescore
  22. 2026-07-06 16:27 UTCEPSS rescore
  23. 2026-07-06 16:27 UTCEPSS rescore
  24. 2026-07-06 02:23 UTCEPSS rescore
  25. 2026-07-06 02:23 UTCEPSS rescore
Show 7 more
  1. 2026-07-05 02:30 UTCEPSS rescore
  2. 2026-07-04 06:31 UTCEPSS rescore
  3. 2026-07-01 15:06 UTCEPSS rescore
  4. 2026-06-30 23:22 UTCEPSS rescore
  5. 2026-06-30 04:37 UTCEG score recompute
  6. 2026-06-30 04:37 UTCVendor advisory
  7. 2026-06-30 04:32 UTCNVD updatefirst tracked

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-33219?
CVE-2026-33219 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, 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…
When was CVE-2026-33219 disclosed?
CVE-2026-33219 was first published in the National Vulnerability Database on March 25, 2026, with the most recent update on July 20, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-33219 actively exploited?
CVE-2026-33219 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 41.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-33219?
CVE-2026-33219 has a CVSS v3 base score of 5.3 (NVD). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-33219?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33219, 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-2026-33219

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