onyx

onyx --cves cve-2025-4820

CVE-2025-4820

MEDCloudflare
score
<0.1
cvss
5.3
epss
0.9%
published
2025-06-18
kev added
—
first seen

Cloudflare quiche contains an incorrect congestion window growth vulnerability caused by opportunistic ACK attack manipulation in congestion control, letting unauthenticated remote attackers send data faster than supported after handshake completion.

Timeline

How this CVE moved toward exploitation. Chart: last 30 days — trend score, EPSS, community mentions per day; hover the event lane.

events2025-06-18 — PublishedP2026-10-21 — Tracked by OnyxTscore2026-10-21: score <0.1<0.1epss2026-09-22: epss 0.9%2026-09-23: epss 0.9%2026-09-24: epss 0.9%2026-09-25: epss 0.9%2026-09-26: epss 0.9%2026-09-27: epss 0.9%2026-09-29: epss 0.9%2026-09-30: epss 0.9%2026-10-01: epss 0.9%2026-10-02: epss 0.9%2026-10-03: epss 0.9%2026-10-04: epss 0.9%2026-10-05: epss 0.9%2026-10-06: epss 0.9%2026-10-07: epss 0.9%2026-10-08: epss 0.9%2026-10-09: epss 0.9%2026-10-10: epss 0.9%2026-10-11: epss 0.9%2026-10-12: epss 0.9%2026-10-13: epss 0.9%2026-10-14: epss 0.9%2026-10-15: epss 0.9%2026-10-16: epss 0.9%2026-10-18: epss 0.9%2026-10-19: epss 0.9%2026-10-20: epss 0.9%2026-10-21: epss 0.9%0.9%mentions/day0no mentions in 30 days2026-09-22today
  1. Published
  2. Tracked by Onyx

Weaknesses

CWE-770

References 1