Cisco IOS/IOS XE/IOS XE Catalyst SD-WAN SNMP Subsystem stack-based overflow

Summaryinfo

A vulnerability was found in Cisco IOS, IOS XE and IOS XE Catalyst SD-WAN and classified as critical. This affects an unknown part of the component SNMP Subsystem. Executing a manipulation can lead to stack-based overflow. This vulnerability is handled as CVE-2025-20352. The attack can be executed remotely. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Cisco IOS, IOS XE and IOS XE Catalyst SD-WAN (the affected version is unknown). This vulnerability affects an unknown code of the component SNMP Subsystem. The manipulation with an unknown input leads to a stack-based overflow vulnerability. The CWE definition for the vulnerability is CWE-121. A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function). As an impact it is known to affect availability. CVE summarizes:

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow the following: An authenticated, remote attacker with low privileges could cause a denial of service (DoS) condition on an affected device that is running Cisco IOS Software or Cisco IOS XE Software. To cause the DoS, the attacker must have the SNMPv2c or earlier read-only community string or valid SNMPv3 user credentials. An authenticated, remote attacker with high privileges could execute code as the root user on an affected device that is running Cisco IOS XE Software. To execute code as the root user, the attacker must have the SNMPv1 or v2c read-only community string or valid SNMPv3 user credentials and administrative or privilege 15 credentials on the affected device. An attacker could exploit this vulnerability by sending a crafted SNMP packet to an affected device over IPv4 or IPv6 networks. This vulnerability is due to a stack overflow condition in the SNMP subsystem of the affected software. A successful exploit could allow a low-privileged attacker to cause the affected system to reload, resulting in a DoS condition, or allow a high-privileged attacker to execute arbitrary code as the root user and obtain full control of the affected system. Note: This vulnerability affects all versions of SNMP.

The advisory is shared for download at sec.cloudapps.cisco.com. This vulnerability was named CVE-2025-20352 since 10/10/2024. The exploitation appears to be easy. The attack can be initiated remotely. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 10/29/2025).

It is declared as attacked. The vulnerability scanner Nessus provides a plugin with the ID 266454 (Cisco IOS Software SNMP DoS RCE (cisco-sa-snmp-x4LPhte)), which helps to determine the existence of the flaw in a target environment. This issue was added on 09/29/2025 to the CISA Known Exploited Vulnerabilities Catalog with a due date of 10/20/2025:

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Zero-Day.cz (1034), Tenable (266454) and EUVD (EUVD-2025-31023). Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• IOS
• IOS XE
• IOS XE Catalyst SD-WAN

License

• commercial

Website

• Vendor: https://www.cisco.com/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion