CVE-2026-62389

✕ Withdrawn — historical dataHIGHPre-NVD 7.5
7.5CVSS
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

ws before 8.21.1 contains a memory exhaustion vulnerability in lib/receiver.js where the fragment guard only triggers when fragment count reaches maxFragments, allowing attackers to exhaust memory by sending incomplete fragmented WebSocket messages. Attackers can send a text frame with FIN=0 followed by continuation frames without completing the sequence, causing each fragment to be stored as a separate Buffer object with significant overhead, enabling denial of service through heap exhaustion.

CVSS v3
7.5
EchelonGraph score
Not yet assessedThis CVE record was withdrawn by its numbering authority, so there is no vulnerability to rate.
EG Score
—
EG Risk
—
EPSS PROB
0%
EPSS %ILE
37%
KEV
Not listed

Published

July 15, 2026

Last Modified

July 28, 2026

Advisory Details (4)

Auto-updated Jul 15, 2026
Patch available. Sources: github_commit, github_release.
generic

ws < 8.21.1 Default maxFragments Allows Memory Exhaustion DoS | Advisories | VulnCheck

https://www.vulncheck.com/advisories/ws-default-maxfragments-allows-memory-exhaustion-dos
github_release Patch Available

Release 8.21.1 (websockets/ws)

Patch available: websockets/ws 8.21.1

https://github.com/websockets/ws/releases/tag/8.21.1
generic

Default maxFragments still allows memory-exhaustion DoS (incomplete GHSA-96hv-2xvq-fx4p fix) · Issue #2331 · websockets/ws · GitHub

https://github.com/websockets/ws/issues/2331
github_commit Patch Available

commit f197ac651409 (websockets/ws)

Patch available: websockets/ws 8.21.1 (contains commit f197ac651409)

https://github.com/websockets/ws/commit/f197ac65140920bdcecdab74bfc69c2d7858e55d

Vendor Advisories for CVE-2026-62389(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 1× in last 7d / 7× 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. 2026-09-11 21:45 UTCGHSA enrichment
  2. 2026-09-05 20:50 UTCGHSA enrichment
  3. 2026-08-30 03:51 UTCGHSA enrichment
  4. 2026-08-26 12:00 UTCGHSA enrichment
  5. 2026-08-23 10:37 UTCGHSA enrichment
  6. 2026-08-20 09:29 UTCGHSA enrichment
  7. 2026-08-17 08:22 UTCGHSA enrichment
  8. 2026-08-14 07:15 UTCGHSA enrichment
  9. 2026-08-11 06:08 UTCGHSA enrichment
  10. 2026-08-08 05:02 UTCGHSA enrichment
  11. 2026-08-05 03:55 UTCGHSA enrichment
  12. 2026-08-02 02:48 UTCEG score recompute
  13. 2026-08-02 02:48 UTCGHSA enrichment
  14. 2026-07-30 01:41 UTCEG score recompute▼ 7.50
  15. 2026-07-30 01:41 UTCGHSA enrichment
  16. 2026-07-30 01:30 UTCEPSS rescore
  17. 2026-07-30 01:30 UTCEPSS rescore
  18. 2026-07-29 13:40 UTCGHSA enrichment
  19. 2026-07-29 01:53 UTCEG score recompute
  20. 2026-07-29 01:53 UTCGHSA enrichment
  21. 2026-07-28 15:37 UTCEPSS rescore
  22. 2026-07-28 14:06 UTCGHSA enrichment
  23. 2026-07-28 02:20 UTCEG score recompute
  24. 2026-07-28 02:20 UTCGHSA enrichment
  25. 2026-07-27 22:56 UTCEG score recompute
Show 30 more
  1. 2026-07-27 22:56 UTCGHSA enrichment
  2. 2026-07-27 14:14 UTCEPSS rescore
  3. 2026-07-27 11:09 UTCGHSA enrichment
  4. 2026-07-26 23:23 UTCEG score recompute
  5. 2026-07-26 23:23 UTCGHSA enrichment
  6. 2026-07-26 14:54 UTCEPSS rescore
  7. 2026-07-26 14:54 UTCEPSS rescore
  8. 2026-07-26 11:34 UTCEG score recompute
  9. 2026-07-26 11:33 UTCGHSA enrichment
  10. 2026-07-25 14:18 UTCEPSS rescore
  11. 2026-07-25 14:18 UTCEPSS rescore
  12. 2026-07-24 14:18 UTCEPSS rescore
  13. 2026-07-24 14:18 UTCEPSS rescore
  14. 2026-07-23 14:18 UTCEPSS rescore
  15. 2026-07-23 14:18 UTCEPSS rescore
  16. 2026-07-23 03:22 UTCEG score recompute
  17. 2026-07-22 14:08 UTCEPSS rescore
  18. 2026-07-22 14:08 UTCEPSS rescore
  19. 2026-07-21 15:25 UTCEPSS rescore
  20. 2026-07-21 15:25 UTCEPSS rescore
  21. 2026-07-20 17:08 UTCEPSS rescore
  22. 2026-07-19 14:31 UTCEPSS rescore
  23. 2026-07-19 02:29 UTCEPSS rescore
  24. 2026-07-18 10:04 UTCEPSS rescore
  25. 2026-07-17 04:47 UTCGHSA enrichment
  26. 2026-07-16 17:03 UTCEPSS rescore
  27. 2026-07-16 17:01 UTCGHSA enrichment
  28. 2026-07-16 05:15 UTCGHSA enrichment
  29. 2026-07-15 17:29 UTCEG score recompute
  30. 2026-07-15 17:28 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-62389?
CVE-2026-62389 is a high vulnerability published on July 15, 2026. ws before 8.21.1 contains a memory exhaustion vulnerability in lib/receiver.js where the fragment guard only triggers when fragment count reaches maxFragments, allowing attackers to exhaust memory by sending incomplete fragmented WebSocket messages. Attackers can send a text frame with FIN=0…
When was CVE-2026-62389 disclosed?
CVE-2026-62389 was first published in the National Vulnerability Database on July 15, 2026, with the most recent update on July 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-62389 actively exploited?
CVE-2026-62389 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 63.2% of all scored CVEs.
What is the CVSS score of CVE-2026-62389?
CVE-2026-62389 has a CVSS v4.0 base score of 7.5 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-62389?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-62389, 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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