CVE-2024-20309

MEDIUM
Published Mar 27, 2024 Modified Jul 30, 2025 CWE-828

Description

A vulnerability in auxiliary asynchronous port (AUX) functions of Cisco IOS XE Software could allow an authenticated, local attacker to cause an affected device to reload or stop responding. This vulnerability is due to the incorrect handling of specific ingress traffic when flow control hardware is enabled on the AUX port. An attacker could exploit this vulnerability by reverse telnetting to the AUX port and sending specific data after connecting. A successful exploit could allow the attacker to cause the device to reset or stop responding, resulting in a denial of service (DoS) condition.

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CVSS v3.1 Score

5.6
MEDIUM
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H

Weakness Type (CWE)

CWE-828 CWE-828

Affected Products

Vendor Product
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe
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cisco ios_xe
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cisco ios_xe
cisco ios_xe
cisco ios_xe
cisco ios_xe

References

Frequently Asked Questions

What is CVE-2024-20309? +
A vulnerability in auxiliary asynchronous port (AUX) functions of Cisco IOS XE Software could allow an authenticated, local attacker to cause an affected device to reload or stop responding. This vulnerability is due to the incorrect handling of specific ingress traffic when flow control hardware is enabled on the AUX port. An attacker could exploit this vulnerability by reverse telnetting to the AUX port and sending specific data after connecting. A successful exploit could allow the attacker to cause the device to reset or stop responding, resulting in a denial of service (DoS) condition. It has a CVSS v3.1 base score of 5.6 (MEDIUM).
How severe is CVE-2024-20309? +
CVE-2024-20309 has a CVSS v3.1 score of 5.6 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2024-20309? +
CVE-2024-20309 affects products from cisco, specifically: ios_xe. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2024-20309? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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