CVE-2023-20126Network attack vector

Unauthenticated code execution via unprotected firmware upgrade

Published May 4, 2023 · Updated Oct 28, 2024

Authentication bypass in all Cisco SPA112 firmware releases allows remote attackers to execute arbitrary code through the web interface. The firmware upgrade function omits authentication and accepts an attacker-supplied firmware image, which the device installs and runs. No credentials or user interaction are required, and successful exploitation grants full privileges while replacing device firmware.

CVSS severity9.8
Critical
EPSS probability36.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in all Cisco SPA112 firmware releases allows remote attackers to execute arbitrary code through the web interface. The firmware upgrade function omits authentication and accepts an attacker-supplied firmware image, which the device installs and runs. No credentials or user interaction are required, and successful exploitation grants full privileges while replacing device firmware.

The record

CVE
CVE-2023-20126
Published
May 4, 2023
Updated
Oct 28, 2024
Vendor
ClamAV
Product
Cisco Small Business IP Phones
Classifications
CWE-306, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 4, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2024Record 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=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Small Business IP Phonesversion=n/a

Published CVSS scores

9.8CiscoCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:X/RL:X/RC:X

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

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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