# Cisco IOS and IOS XE: IOS and IOS XE Software SNMP Denial of Service and Remote Code Execution Vulnerability · pwn.watch

> Cisco IOS and IOS XE contains a stack-based buffer overflow vulnerability in the Simple Network Management Protocol (SNMP) subsystem that could allow for denial of service or remote code execution. 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. Added to CISA KEV on 2025-09-29.

Page: https://pwn.watch/i/cisco-ios-and-ios-xe-cve-2025-20352 · generated 2026-10-22T22:00:08.805Z

## Status
- Severity: high · status: closed · patch: patched
- Product: Cisco IOS and IOS XE
- Started: 2025-09-29 · closed: 2025-09-29
- CVEs: CVE-2025-20352
- Affected: See vendor advisory / CISA notes (versions not always listed in KEV feed)
- Fixed in: See vendor advisory linked in sources

## Follow this incident
- RSS (one item per update): https://pwn.watch/i/cisco-ios-and-ios-xe-cve-2025-20352/feed.xml
- JSON Feed: https://pwn.watch/i/cisco-ios-and-ios-xe-cve-2025-20352/feed.json
- Full data (timeline, sources, posts, agentBrief): https://pwn.watch/i/cisco-ios-and-ios-xe-cve-2025-20352.json
- This file: https://pwn.watch/i/cisco-ios-and-ios-xe-cve-2025-20352/llms.txt

## Updates (newest first)
- 2025-09-29: CISA added CVE-2025-20352 to the KEV catalog (due 2025-10-20).

## Fix brief
# Security brief: Cisco IOS and IOS XE: IOS and IOS XE Software SNMP Denial of Service and Remote Code Execution Vulnerability

Source: https://pwn.watch/i/cisco-ios-and-ios-xe-cve-2025-20352 · status: closed (closed Sep 29, 2025) · severity: high · updated Sep 29, 2025

## Patch status
**PATCHED: fixed releases exist. Upgrade to a fixed version.**

## What it is
Cisco IOS and IOS XE contains a stack-based buffer overflow vulnerability in the Simple Network Management Protocol (SNMP) subsystem that could allow for denial of service or remote code execution. 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. Added to CISA KEV on 2025-09-29.

Severity detail: CVSS 7.7 (CNA, v3.1); actively exploited (CISA KEV)

- Product: Cisco IOS and IOS XE
- CVE / advisory ids: CVE-2025-20352

## Affected versions
- See vendor advisory / CISA notes (versions not always listed in KEV feed)

## Check whether you're affected
No generic command applies (the product is a hosted service, appliance or desktop app). Check the installed version in its admin UI / About screen and compare with the versions above.

## Fix
Upgrade to one of these fixed versions (or later on the same branch):
- See vendor advisory linked in sources

After upgrading, re-run the checks above and redeploy/restart the affected services.

## Latest updates
- Sep 29, 2025: CISA added CVE-2025-20352 to the KEV catalog (due 2025-10-20).

## Advisories
- [Cisco advisory: Cisco IOS and IOS XE](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snmp-x4LPhte) (Cisco)
- [NVD: CVE-2025-20352](https://nvd.nist.gov/vuln/detail/CVE-2025-20352) (NVD)
- [CISA Known Exploited Vulnerabilities Catalog](https://www.cisa.gov/known-exploited-vulnerabilities-catalog) (CISA)

## Caveats
Derived from CISA KEV JSON feed catalogVersion 2026.10.21. CVSS from the CVE record (cvelistV5). Exact affected/fixed version strings are not always in the KEV record; verify against the vendor advisory URL. startedAt uses dateAdded (exploitation may have begun earlier; many entries are older CVEs newly confirmed as exploited in 2025).

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Machine-readable: https://pwn.watch/i/cisco-ios-and-ios-xe-cve-2025-20352.json · all incidents: https://pwn.watch/incidents.json. Verify against the vendor advisory before changing production systems.