CVE-2025-7635Public exploit

Root access via passwordless Telnet accounts

Published Sep 9, 2025 · Updated Sep 12, 2025

Missing authentication in Calix GigaCenter ONT 844E, 844G, 844GE, and 854GE allows remote attackers on the LAN to gain root access. The Quantenna SoC interface enables Telnet during boot and accepts the admin or root username without requesting a password. LAN access to that internal interface is required, after which the session grants high-privilege command access and permits device data to be read or changed.

CVSS severity8.7
High
EPSS probability0.29%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authentication in Calix GigaCenter ONT 844E, 844G, 844GE, and 854GE allows remote attackers on the LAN to gain root access. The Quantenna SoC interface enables Telnet during boot and accepts the admin or root username without requesting a password. LAN access to that internal interface is required, after which the session grants high-privilege command access and permits device data to be read or changed.

The record

CVE
CVE-2025-7635
Published
Sep 9, 2025
Updated
Sep 12, 2025
Vendor
Calix
Product
GigaCenter ONT
Classifications
CWE-306, CAPEC-114, T1210
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=844E
  2. Affected versionversion=844G
  3. Affected versionversion=844GE
  4. Affected versionversion=854GE

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Calix · GigaCenter ONTversion=844E; version=844G; version=844GE; version=854GE

Published CVSS scores

8.7Fluid AttacksCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.7NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
CAPEC-114Authentication Abuse
T1210Exploitation of Remote Services

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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