onyx

onyx --cves cve-2026-48521

CVE-2026-48521

MEDPOCEnvoy Proxy
score
12.6
cvss
5.9
epss
0.7%
published
2026-09-21
kev added
—
first seen

Envoy < 1.36.10, 1.37.6, 1.38.4, and 1.39.1 contains a denial of service caused by dereferencing a null transport_socket_options pointer in ProdClusterManagerFactory::allocateConnPool when selecting an HTTP/3 connection pool, letting attackers crash Envoy workers, exploit requires HTTP/3 enabled and specific LoadBalancerContext with no transport-socket options.

Timeline

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

events2026-09-21 — PublishedP2026-10-21 — Tracked by OnyxT2026-10-21 — Public PoCXscore2026-10-21: score 12.612.6epss2026-09-22: epss 0.7%2026-09-23: epss 0.7%2026-09-24: epss 0.7%2026-09-25: epss 0.7%2026-09-26: epss 0.7%2026-09-27: epss 0.7%2026-09-29: epss 0.7%2026-09-30: epss 0.7%2026-10-01: epss 0.7%2026-10-02: epss 0.7%2026-10-03: epss 0.7%2026-10-04: epss 0.7%2026-10-05: epss 0.7%2026-10-06: epss 0.7%2026-10-07: epss 0.7%2026-10-08: epss 0.7%2026-10-09: epss 0.7%2026-10-10: epss 0.7%2026-10-11: epss 0.7%2026-10-12: epss 0.7%2026-10-13: epss 0.7%2026-10-14: epss 0.7%2026-10-15: epss 0.7%2026-10-16: epss 0.7%2026-10-18: epss 0.7%2026-10-19: epss 0.7%2026-10-20: epss 0.7%2026-10-21: epss 0.7%0.7%mentions/day0no mentions in 30 days2026-09-22today
  1. Published
  2. Tracked by Onyx
  3. Public PoC

Exploit availability

Public PoC flagged by vulnx; no direct exploit link among the citations.

Weaknesses

CWE-476

References 9