CVE intelligence and bounded remediation

CVE-2025-7635 — Calix Calix Gigacenter Ont security vulnerability

High CVSS 8.7

Unauthenticated Telnet access vulnerability in Calix GigaCenter ONT allows root access.This issue affects GigaCenter ONT: 844E, 844G, 844GE, 854GE.

Severity
High
CVSS
8.7 (4.0)
Published
2025-09-09
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-306

Affected products

  • calix / calix_gigacenter_ont
  • calix / calix_gigacenter_ont / 844e
  • calix / calix_gigacenter_ont / 844g
  • calix / calix_gigacenter_ont / 844ge
  • calix / calix_gigacenter_ont / 854ge

Matched remediation archetype

Authentication bypass and missing authentication

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Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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