CVE-2025-20352

Cisco IOS and IOS XE: Software SNMP Denial of Service and Remote Code Execution

As of , CVE-2025-20352 in Cisco IOS and IOS XE is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch soon.

Exploited
Yes: CISA listed it on 29 September 2025
US federal deadline
20 October 202521 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.39Higher than 98% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
Vendor advice: sec.cloudapps.cisco.comLinks below, from CISA's entry.

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.

CISA's required action

What the flaw 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.

CISA's 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.

The CVE record's description, from cisco

CVE published
24 September 2025
Assigned by
cisco
CVSS
7.7 High (CVSS 3.1, from the CNA)
CWE-121
Stack-based Buffer Overflow
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
total

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. CISA changed its entry. Edited: name.
  4. The US federal deadline to fix it.

IOS and IOS XE: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2017-3881Remote Code ExecutionCisco IOS and IOS XEPatch this weekMetasploit module; EPSS 0.990.99
CVE-2018-0171Software Smart Install Remote Code ExecutionCisco IOS and IOS XEPatch this weekEPSS 0.990.99
CVE-2023-20109Group Encrypted Transport VPN Out-of-Bounds WriteCisco IOS and IOS XEPatch soon0.02

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