CVE-2026-62389

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-15. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
7.5
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 7.5Exploit: NoneExposed: 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
EG Score
7.5(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: 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
Severity75% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
36.7%
KEV
Not listed

Published

July 15, 2026

Last Modified

July 15, 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 13× in last 7d / 19× 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. 2026-07-24 14:18 UTCEPSS rescore
  2. 2026-07-24 14:18 UTCEPSS rescore
  3. 2026-07-23 14:18 UTCEPSS rescore
  4. 2026-07-23 14:18 UTCEPSS rescore
  5. 2026-07-23 03:22 UTCEG score recompute
  6. 2026-07-22 14:08 UTCEPSS rescore
  7. 2026-07-22 14:08 UTCEPSS rescore
  8. 2026-07-21 15:25 UTCEPSS rescore
  9. 2026-07-21 15:25 UTCEPSS rescore
  10. 2026-07-20 17:08 UTCEPSS rescore
  11. 2026-07-19 14:31 UTCEPSS rescore
  12. 2026-07-19 02:29 UTCEPSS rescore
  13. 2026-07-18 10:04 UTCEPSS rescore
  14. 2026-07-17 04:47 UTCGHSA enrichment
  15. 2026-07-16 17:03 UTCEPSS rescore
  16. 2026-07-16 17:01 UTCGHSA enrichment
  17. 2026-07-16 05:15 UTCGHSA enrichment
  18. 2026-07-15 17:29 UTCEG score recompute
  19. 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. 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 36.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-62389?
CVE-2026-62389 has a CVSS v3 base score of 7.5 (NVD).
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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