Cisco IOS and IOS XE
CVE-2025-20352
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.
What this means for your business
- It affects Cisco IOS and IOS XE. It matters if your company, or a supplier that handles your data, runs it.
- Attackers are already using it. CISA added it to its list of flaws used in real attacks on 29 September 2025.
- FIRST's prediction model gives it a 39% chance of attack attempts being seen in the next 30 days, ranking above 98% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Cisco IOS and IOS XE.
- 2If you do, follow CISA's required action below. No patch reference has been published yet.
- 3Treat it as urgent. US federal agencies must fix it by 20 October 2025. That deadline does not apply to private companies, but it shows how seriously CISA takes it.
- 4Because attackers have used it, check the affected systems for signs of a break-in, not only for the update.
Not sure if your company is exposed?
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Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA’s wording, unedited.
Scoring
- CVSS
- Not yet scored
Dates
- Published
- 2025-09-29
- Added to KEV
- 2025-09-29
- Remediation due
- 2025-10-20
- Sources
- CISA KEV