CVE-2020-3524

6.8 MEDIUM 0.3% exploit odds Fix listed

What it is

A vulnerability in the Cisco IOS XE ROM Monitor (ROMMON) Software for Cisco 4000 Series Integrated Services Routers, Cisco ASR 920 Series Aggregation Services Routers, Cisco ASR 1000 Series Aggregation Services Routers, and Cisco cBR-8 Converged Broadband Routers could allow an unauthenticated, physical attacker to break the chain of trust and load a compromised software image on an affected device. The vulnerability is due to the presence of a debugging configuration option in the affected software. An attacker could exploit this vulnerability by connecting to an affected device through the console, forcing the device into ROMMON mode, and writing a malicious pattern using that specific option on the device. A successful exploit could allow the attacker to break the chain of trust and load a compromised software image on the affected device. A compromised software image is any software image that has not been digitally signed by Cisco.

At a glance

Exploitability: Can be exploited with physical access without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2020-09-24 18:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 03:18 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 6.8 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2020-09-24 18:15 UTC
Last modified: 2026-06-17 03:18 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-284 · Improper access control
Record status: Modified

Affected

Cisco iOS Xe Rom Monitor < 16.2\(1r\)
Cisco iOS Xe Rom Monitor < 15.6\(18r\)
Cisco iOS Xe Rom Monitor < 16.4\(1r\)s

Attack profile CVSS 3.1 · 6.8

Attack vector: Physical
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2020-3524.md and follow it. Check whether this project is affected by CVE-2020-3524. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record