CVE-2024-20309
A vulnerability in auxiliary asynchronous port (AUX) functions of Cisco IOS XE Software could...
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.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
5.6
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.
- Record
CVE-2024-20309- CVSS 3.1
- 5.6 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-828
- Updated
- 2026-11-02
EUVDEUVD-2024-18024
5.6
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.
- Record
EUVD-2024-18024- CVSS 3.1
- 5.6 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-p2c3-pjg6-q385
5.6
A vulnerability in auxiliary asynchronous port (AUX) functions of Cisco IOS XE Software could...
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.
- Record
GHSA-p2c3-pjg6-q385- CVSS 3.1
- 5.6 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H - Weakness
- CWE-828
- Updated
- 2026-11-02
NVD
5.6
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.
- Record
CVE-2024-20309- CVSS 3.1
- 5.6 Medium
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H - CVSS 3.1
- 5.5 Medium
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-828
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-20309 is a medium vulnerability (CVSS 5.6) in Cisco Ios Xe Software, published March 27, 2024. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.10%, the 0th percentile. No source names a fixed version.