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Known exploited vulnerability

CVE-2025-20352

highCVSS 3.1 7.7In CISA KEVEPSS 41%Published · Cisco

The short answer

CVE-2025-20352 affects Cisco IOS and is rated high (CVSS 7.7). CISA added it to the Known Exploited Vulnerabilities catalog on 2025-09-29: attackers are using it, so patch it first.

What it is

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.

Weakness: CWE-121.

Severity

7.7 high

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H

Exploited (CISA KEV)

Yes, since Sep 29, 2025

Federal due date Oct 20, 2025

EPSS, next 30 days

41%

Higher than 99% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Changed
Confidentiality impact
None
Integrity impact
None
Availability impact
High

What CISA says to do

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

Affected products

IOS, Cisco IOS XE Software, Cisco IOS XE Catalyst SD-WAN. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2025-20352 being exploited?

Yes. CISA added CVE-2025-20352 to its Known Exploited Vulnerabilities catalog on 2025-09-29, with a federal remediation due date of 2025-10-20.

How do I fix CVE-2025-20352?

CISA's 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.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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