Which versions of Calix Gigacenter Ont are affected by CVE-2025-7635?

Organizations using Unauthenticated Telnet access vulnerability in Calix GigaCenter ONT face significant risk from CVE-2025-7635, a missing authentication vulnerability rated CVSS 8.7.

Is there a public PoC exploit available for CVE-2025-7635?

Yes, a public proof-of-concept exploit is available for CVE-2025-7635. Prioritise patching immediately. EPSS: 0.0%.

How to fix or mitigate CVE-2025-7635?

Within 7 days: Identify all affected systems and apply vendor patches promptly. Audit authentication configurations and rotate any potentially compromised credentials.

Calix Gigacenter Ont CVE-2025-7635

Q: What is the CVSS score of CVE-2025-7635?

CVE-2025-7635 has a CVSS 4.0 base score of 8.7 (High). CVSS vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.0%.

HIGH

Missing Authentication for Critical Function (CWE-306)

2025-09-09 help@fluidattacks.com

Authentication Bypass Calix Gigacenter Ont

8.7

CVSS 4.0 · NVD

Severity by source

NVD PRIMARY

8.7 HIGH

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Adjacent

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:11 vuln.today

PoC Detected

Dec 22, 2025 - 20:01 vuln.today

Public exploit code

CVE Published

Sep 09, 2025 - 20:15 nvd

HIGH 8.7

DescriptionCVE.org

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

AnalysisAI

Unauthenticated Telnet access vulnerability in Calix GigaCenter ONT allows root access. Rated high severity (CVSS 8.7), this vulnerability is no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified as Missing Authentication for Critical Function (CWE-306), which allows attackers to access critical functionality without authentication. Unauthenticated Telnet access vulnerability in Calix GigaCenter ONT allows root access. Affected products include: Calix Calix Gigacenter Ont.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Require authentication for all sensitive operations, implement defense in depth.

CVE-2025-7635 vulnerability details – vuln.today

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