CVE-2021-20120Public exploitNetwork attack vector

Configuration changes via unprotected cross-site requests

Published Oct 21, 2021 · Updated Aug 3, 2024

Cross-site request forgery in ARRIS SURFboard SB8200 firmware AB01.02.053.01_112320_193.0A.NSH allows remote attackers to change modem settings. The administration web interface accepts a cross-origin POST to changepwd_tab.html without an anti-CSRF token or origin validation, treating the victim browser's request as authorized. The victim must visit attacker-controlled content while able to reach the modem's local management address, enabling administrative password and configuration changes.

CVSS severity8.0
High
EPSS probability0.56%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site request forgery in ARRIS SURFboard SB8200 firmware AB01.02.053.01_112320_193.0A.NSH allows remote attackers to change modem settings. The administration web interface accepts a cross-origin POST to changepwd_tab.html without an anti-CSRF token or origin validation, treating the victim browser's request as authorized. The victim must visit attacker-controlled content while able to reach the modem's local management address, enabling administrative password and configuration changes.

The record

CVE
CVE-2021-20120
Published
Oct 21, 2021
Updated
Aug 3, 2024
Vendor
ARRIS
Product
SURFboard SB8200
Classifications
CWE-352
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=AB01.02.053.01_112320_193.0A.NSH

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ARRIS · SURFboard SB8200version=AB01.02.053.01_112320_193.0A.NSH

Published CVSS scores

8.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
8.0TenableCVSS:3.0/AV:A/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-352Cross-Site Request Forgery (CSRF)

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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