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onyx --cves cve-2025-66220

CVE-2025-66220

MEDPOCEnvoy Proxy
score
<0.1
cvss
5.0
epss
0.2%
published
2025-12-03
kev added
—
first seen

Envoy <= 1.33.12, 1.34.10, 1.35.6, 1.36.2 contains a broken authentication caused by incorrect mTLS certificate matcher handling embedded null bytes in OTHERNAME SAN values, letting attackers bypass certificate validation, exploit requires crafted certificate with embedded null byte.

Timeline

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

events2025-12-03 — PublishedP2026-10-21 — Tracked by OnyxT2026-10-21 — Public PoCXscore2026-10-21: score <0.1<0.1epss2026-09-22: epss 0.2%2026-09-23: epss 0.2%2026-09-24: epss 0.2%2026-09-25: epss 0.2%2026-09-26: epss 0.2%2026-09-27: epss 0.2%2026-09-29: epss 0.2%2026-09-30: epss 0.2%2026-10-01: epss 0.2%2026-10-02: epss 0.2%2026-10-03: epss 0.2%2026-10-04: epss 0.2%2026-10-05: epss 0.2%2026-10-06: epss 0.2%2026-10-07: epss 0.2%2026-10-08: epss 0.2%2026-10-09: epss 0.2%2026-10-10: epss 0.2%2026-10-11: epss 0.2%2026-10-12: epss 0.2%2026-10-13: epss 0.2%2026-10-14: epss 0.2%2026-10-15: epss 0.2%2026-10-16: epss 0.2%2026-10-18: epss 0.2%2026-10-19: epss 0.2%2026-10-20: epss 0.2%2026-10-21: epss 0.2%0.2%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-170

References 1