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 57% 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
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1.0%CVSS: 5.3Exploit: None knownExposed services: Not assessed

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
5.3MEDIUMmedium confidence
EG Risk
24
EG Risk 24/100

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%
EPSS PROB
1.0%
EPSS %ILE
61st
KEV
Not listed

Published

March 25, 2026

Last Modified

September 9, 2026

Advisory Details (10)

Auto-updated Jul 19, 2026
Patch available. Sources: github, redhat.
redhatMentions a patch (unverified)
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
redhatMentions a patch (unverified)

cve-details

https://access.redhat.com/security/cve/CVE-2026-33219
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:23345
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:22347
redhatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:21769
githubMentions a patch (unverified)

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

https://github.com/nats-io/nats-server/security/advisories/GHSA-8r68-gvr4-jh7j
githubMentions a patch (unverified)

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 / EcosystemFix (by version range) / 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 rangeFix by version rangeDependents
github.com/nats-io/nats-server—
  • every version on: no fix on record
—
github.com/nats-io/nats-server/v2—
  • every version up to 2.11.15: fixed in 2.11.15
  • 2.12.0-RC.1 up to 2.12.6: fixed in 2.12.6
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
nats-server2.10.1-1 ... 2.9.19-1 (15 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
nats-server2.10.27-1 ... 2.14.6-1 (6 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
nats-server2.10.27-1, 2.12.4-1
  • every version up to 2.12.6-1: fixed in 2.12.6-1
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 7× in last 7d / 25× 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 155 total refreshes for this CVE.

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

Related CVEs(same product + 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 on March 25, 2026, with the most recent update on September 9, 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 1.0% probability of exploitation in the next 30 days (61st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-33219?
CVE-2026-33219 has a CVSS base score of 5.3 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-33219?
A fix for CVE-2026-33219 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-33219 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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