CVE-2026-62389
ws <8.21.1 memory-exhaustion DoS via fragmented WebSocket frames
Is CVE-2026-62389 being exploited?
Not confirmed. CVE-2026-62389 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked.
How severe is CVE-2026-62389?
CVE-2026-62389 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-62389?
Yes. A fix has been recorded for CVE-2026-62389. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-62389 affect?
CVE-2026-62389 affects ws < 8.21.1, Node.js applications using ws, WebSocket servers. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-62389?
Upgrade ws to >=8.21.1 and apply connection/rate limits on WebSocket endpoints.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote denial-of-service: heap exhaustion by sending incomplete fragmented WebSocket frames, causing OOM/crash of Node.js ws servers.
Patch when possible