CVE-2025-20352
Published: 24 September 2025
Summary
CVE-2025-20352 is a high-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Cisco Ios. Its CVSS base score is 7.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 14.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly remediates the stack-based buffer overflow vulnerability in the SNMP subsystem by requiring timely application of vendor-provided patches.
Requires validation of SNMP packet inputs to prevent crafted packets from triggering the buffer overflow condition.
Implements memory protections such as stack guards to mitigate successful exploitation of the stack overflow for code execution.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Buffer overflow in SNMP service allows remote authenticated exploitation for RCE (or DoS) on network devices, directly mapping to public-facing app and remote service exploitation techniques.
NVD Description
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…
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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.
Deeper analysisAI
CVE-2025-20352 is a stack-based buffer overflow vulnerability (CWE-121) in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software and Cisco IOS XE Software. The issue affects all versions of SNMP and has a CVSS v3.1 base score of 7.7 (AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H). It stems from improper handling of crafted SNMP packets sent over IPv4 or IPv6 networks, potentially leading to a denial-of-service (DoS) condition or arbitrary code execution depending on attacker privileges.
An authenticated remote attacker with low privileges, such as SNMPv2c or earlier read-only community string or valid SNMPv3 user credentials, can exploit the vulnerability to cause the affected device to reload, resulting in a DoS condition. A high-privileged authenticated remote attacker, possessing SNMPv1 or v2c read-only community string or valid SNMPv3 credentials plus administrative or privilege level 15 access, can execute arbitrary code as the root user on Cisco IOS XE Software devices, potentially gaining full control of the system.
The Cisco Security Advisory at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-x4LPhte provides details on affected software releases and available patches or workarounds. Security practitioners should consult this advisory for mitigation guidance, including software upgrades.
This vulnerability is listed in the CISA Known Exploited Vulnerabilities Catalog at https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-20352, indicating active exploitation in the wild.
Details
- CWE(s)
- KEV Date Added
- 29 September 2025