CVE-2026-33219

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5%, top 58% of all CVEs by exploit prediction. 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: epss, secondary
Trending — 3 sources updated this week
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 5.3Exploit: None knownExposed: 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(medium)
EG Risk
24(Track)
EG Risk 24/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity53% × 45%
Exploitation1% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
42%
KEV
Not listed

Published

March 25, 2026

Last Modified

August 24, 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

(5 across 4 ecosystems)
Go(2)
PackageVulnerable rangeFixed inDependents
github.com/nats-io/nats-server———
github.com/nats-io/nats-server/v2—2.12.6—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
nats-server2.10.1-1 ... 2.9.19-1 (14 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
nats-server2.10.27-1, 2.12.4-1, 2.12.6-1, 2.14.1-1, 2.14.3-1——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
nats-server2.10.27-1, 2.12.4-12.12.6-1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 69× 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.

Showing the most recent 100 of 110 total refreshes for this CVE.

  1. 2026-08-25 13:49 UTCEPSS rescore
  2. 2026-08-24 14:17 UTCEPSS rescore
  3. 2026-08-24 13:31 UTCEG score recompute
  4. 2026-08-24 13:31 UTCVendor advisory
  5. 2026-08-24 12:27 UTCEG score recompute
  6. 2026-08-24 12:27 UTCVendor advisory
  7. 2026-08-23 00:19 UTCEPSS rescore
  8. 2026-08-21 23:49 UTCEPSS rescore
  9. 2026-08-20 22:55 UTCEPSS rescore
  10. 2026-08-20 22:55 UTCEPSS rescore
  11. 2026-08-19 17:03 UTCEPSS rescore
  12. 2026-08-18 13:48 UTCEPSS rescore
  13. 2026-08-17 13:47 UTCEPSS rescore
  14. 2026-08-17 12:21 UTCEG score recompute
  15. 2026-08-17 12:21 UTCVendor advisory
  16. 2026-08-17 12:13 UTCEG score recompute
  17. 2026-08-17 12:13 UTCVendor advisory
  18. 2026-08-16 14:56 UTCEPSS rescore
  19. 2026-08-16 10:13 UTCEG score recompute
  20. 2026-08-16 10:13 UTCVendor advisory
  21. 2026-08-16 02:14 UTCEPSS rescore
  22. 2026-08-15 01:30 UTCEPSS rescore
  23. 2026-08-14 13:28 UTCEG score recompute
  24. 2026-08-14 13:28 UTCVendor advisory
  25. 2026-08-14 12:30 UTCEG score recompute
Show 75 more
  1. 2026-08-14 12:30 UTCVendor advisory
  2. 2026-08-14 06:31 UTCEG score recompute
  3. 2026-08-14 06:31 UTCVendor advisory
  4. 2026-08-13 22:00 UTCEPSS rescore
  5. 2026-08-12 20:48 UTCEG score recompute
  6. 2026-08-12 20:48 UTCVendor advisory
  7. 2026-08-12 13:50 UTCEPSS rescore
  8. 2026-08-11 20:52 UTCEG score recompute
  9. 2026-08-11 20:52 UTCVendor advisory
  10. 2026-08-11 00:00 UTCEPSS rescore
  11. 2026-08-10 13:22 UTCEG score recompute
  12. 2026-08-10 13:22 UTCVendor advisory
  13. 2026-08-10 12:27 UTCEG score recompute
  14. 2026-08-10 12:27 UTCVendor advisory
  15. 2026-08-10 04:26 UTCEG score recompute
  16. 2026-08-10 04:26 UTCVendor advisory
  17. 2026-08-09 13:46 UTCEPSS rescore
  18. 2026-08-09 06:07 UTCEG score recompute
  19. 2026-08-09 06:07 UTCVendor advisory
  20. 2026-08-08 16:37 UTCEPSS rescore
  21. 2026-08-07 16:27 UTCEG score recompute
  22. 2026-08-07 16:27 UTCVendor advisory
  23. 2026-08-06 13:46 UTCEPSS rescore
  24. 2026-08-06 00:57 UTCEG score recompute
  25. 2026-08-06 00:57 UTCVendor advisory
  26. 2026-08-05 19:17 UTCEPSS rescore
  27. 2026-08-04 15:10 UTCEPSS rescore
  28. 2026-08-04 10:38 UTCEPSS rescore
  29. 2026-08-03 13:44 UTCEG score recompute
  30. 2026-08-03 13:44 UTCVendor advisory
  31. 2026-08-03 12:49 UTCEG score recompute
  32. 2026-08-03 12:49 UTCVendor advisory
  33. 2026-08-03 10:36 UTCEPSS rescore
  34. 2026-08-02 15:27 UTCEG score recompute
  35. 2026-08-02 15:27 UTCVendor advisory
  36. 2026-08-02 02:27 UTCEPSS rescore
  37. 2026-08-01 04:16 UTCEPSS rescore
  38. 2026-07-30 16:28 UTCEPSS rescore
  39. 2026-07-30 01:30 UTCEPSS rescore
  40. 2026-07-27 14:13 UTCEPSS rescore
  41. 2026-07-27 13:31 UTCEG score recompute
  42. 2026-07-27 13:31 UTCVendor advisory
  43. 2026-07-27 12:41 UTCEG score recompute
  44. 2026-07-27 12:41 UTCVendor advisory
  45. 2026-07-26 14:54 UTCEPSS rescore
  46. 2026-07-26 14:54 UTCEPSS rescore
  47. 2026-07-25 14:18 UTCEPSS rescore
  48. 2026-07-25 14:18 UTCEPSS rescore
  49. 2026-07-24 14:17 UTCEPSS rescore
  50. 2026-07-24 14:17 UTCEPSS rescore
  51. 2026-07-23 14:18 UTCEPSS rescore
  52. 2026-07-23 14:18 UTCEPSS rescore
  53. 2026-07-23 03:09 UTCEG score recompute
  54. 2026-07-22 14:08 UTCEPSS rescore
  55. 2026-07-21 15:24 UTCEPSS rescore
  56. 2026-07-20 17:08 UTCEPSS rescore
  57. 2026-07-19 14:31 UTCEPSS rescore
  58. 2026-07-19 02:29 UTCEPSS rescore
  59. 2026-07-18 10:04 UTCEPSS rescore
  60. 2026-07-18 06:59 UTCOSV refresh
  61. 2026-07-16 17:03 UTCEPSS rescore
  62. 2026-07-16 17:03 UTCEPSS rescore
  63. 2026-07-15 16:57 UTCEPSS rescore
  64. 2026-07-15 16:57 UTCEPSS rescore
  65. 2026-07-15 02:00 UTCEPSS rescore
  66. 2026-07-15 02:00 UTCEPSS rescore
  67. 2026-07-13 22:30 UTCEPSS rescore
  68. 2026-07-13 06:13 UTCEPSS rescore
  69. 2026-07-13 06:13 UTCEPSS rescore
  70. 2026-07-12 05:46 UTCEPSS rescore
  71. 2026-07-11 08:27 UTCEPSS rescore
  72. 2026-07-09 19:10 UTCEPSS rescore
  73. 2026-07-08 15:15 UTCEPSS rescore
  74. 2026-07-07 13:46 UTCEPSS rescore
  75. 2026-07-06 16:27 UTCEPSS rescore

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 August 24, 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 1% probability of exploitation in the next 30 days, which ranks it in the top 57.8% of all scored CVEs.
What is the CVSS score of CVE-2026-33219?
CVE-2026-33219 has a CVSS v3 base score of 5.3 (NVD).
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

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