CVE-2020-3235 | Cisco IOS and IOS XE Software Simple Network Management Protocol Denial of Service Vulnerability

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software and Cisco IOS XE Software on Catalyst 4500 Series Switches could allow an authenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to insufficient input validation when the software processes specific SNMP object identifiers. An attacker could exploit this vulnerability by sending a crafted SNMP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: To exploit this vulnerability by using SNMPv2c or earlier, the attacker must know the SNMP read-only community string for an affected system. To exploit this vulnerability by using SNMPv3, the attacker must know the user credentials for the affected system.

Published: 2020-06-03 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-3235 is rated Moderate Risk (57.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.57%). EPSS rose +1.27% over the last day, indicating growing attacker interest. Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-3235

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.29% 1.57% +1.27%
2 2025-03-30 0.41% 0.29% -0.12%
3 2025-03-29 — 0.41% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-3235

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.7 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.1 4.0 [email protected]
7.7 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.1 4.0 [email protected]
6.3 2.0 MEDIUM
AV:N/AC:M/Au:S/C:N/I:N/A:C Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:C)
Complete availability impact.
 6.8 6.9 [email protected]

Weakness enumeration for CVE-2020-3235

Affected software / configurations for CVE-2020-3235

Vendor Product Version Raw CPE
cisco ios 12.2\(52\)sg cpe:2.3:o:cisco:ios:12.2\(52\)sg:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg1 cpe:2.3:o:cisco:ios:12.2\(53\)sg1:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg2 cpe:2.3:o:cisco:ios:12.2\(53\)sg2:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg3 cpe:2.3:o:cisco:ios:12.2\(53\)sg3:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg4 cpe:2.3:o:cisco:ios:12.2\(53\)sg4:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg5 cpe:2.3:o:cisco:ios:12.2\(53\)sg5:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg6 cpe:2.3:o:cisco:ios:12.2\(53\)sg6:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg7 cpe:2.3:o:cisco:ios:12.2\(53\)sg7:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg8 cpe:2.3:o:cisco:ios:12.2\(53\)sg8:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg9 cpe:2.3:o:cisco:ios:12.2\(53\)sg9:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg10 cpe:2.3:o:cisco:ios:12.2\(53\)sg10:*:*:*:*:*:*:*
cisco ios 12.2\(53\)sg11 cpe:2.3:o:cisco:ios:12.2\(53\)sg11:*:*:*:*:*:*:*
cisco ios 12.2\(54\)sg cpe:2.3:o:cisco:ios:12.2\(54\)sg:*:*:*:*:*:*:*
cisco ios 12.2\(54\)sg1 cpe:2.3:o:cisco:ios:12.2\(54\)sg1:*:*:*:*:*:*:*
cisco ios 12.2\(54\)wo cpe:2.3:o:cisco:ios:12.2\(54\)wo:*:*:*:*:*:*:*
cisco ios 15.0\(1\)ey cpe:2.3:o:cisco:ios:15.0\(1\)ey:*:*:*:*:*:*:*
cisco ios 15.0\(1\)ey2 cpe:2.3:o:cisco:ios:15.0\(1\)ey2:*:*:*:*:*:*:*
cisco ios 15.0\(1\)xo cpe:2.3:o:cisco:ios:15.0\(1\)xo:*:*:*:*:*:*:*
cisco ios 15.0\(1\)xo1 cpe:2.3:o:cisco:ios:15.0\(1\)xo1:*:*:*:*:*:*:*
cisco ios 15.0\(2\)ex2 cpe:2.3:o:cisco:ios:15.0\(2\)ex2:*:*:*:*:*:*:*
cisco ios 15.0\(2\)ex8 cpe:2.3:o:cisco:ios:15.0\(2\)ex8:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg cpe:2.3:o:cisco:ios:15.0\(2\)sg:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg1 cpe:2.3:o:cisco:ios:15.0\(2\)sg1:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg2 cpe:2.3:o:cisco:ios:15.0\(2\)sg2:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg3 cpe:2.3:o:cisco:ios:15.0\(2\)sg3:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg4 cpe:2.3:o:cisco:ios:15.0\(2\)sg4:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg5 cpe:2.3:o:cisco:ios:15.0\(2\)sg5:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg6 cpe:2.3:o:cisco:ios:15.0\(2\)sg6:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg7 cpe:2.3:o:cisco:ios:15.0\(2\)sg7:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg8 cpe:2.3:o:cisco:ios:15.0\(2\)sg8:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg9 cpe:2.3:o:cisco:ios:15.0\(2\)sg9:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg10 cpe:2.3:o:cisco:ios:15.0\(2\)sg10:*:*:*:*:*:*:*
cisco ios 15.0\(2\)sg11 cpe:2.3:o:cisco:ios:15.0\(2\)sg11:*:*:*:*:*:*:*
cisco ios 15.0\(2\)xo cpe:2.3:o:cisco:ios:15.0\(2\)xo:*:*:*:*:*:*:*
cisco ios 15.1\(1\)sg cpe:2.3:o:cisco:ios:15.1\(1\)sg:*:*:*:*:*:*:*
cisco ios 15.1\(1\)sg1 cpe:2.3:o:cisco:ios:15.1\(1\)sg1:*:*:*:*:*:*:*
cisco ios 15.1\(1\)sg2 cpe:2.3:o:cisco:ios:15.1\(1\)sg2:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg cpe:2.3:o:cisco:ios:15.1\(2\)sg:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg1 cpe:2.3:o:cisco:ios:15.1\(2\)sg1:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg2 cpe:2.3:o:cisco:ios:15.1\(2\)sg2:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg3 cpe:2.3:o:cisco:ios:15.1\(2\)sg3:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg4 cpe:2.3:o:cisco:ios:15.1\(2\)sg4:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg5 cpe:2.3:o:cisco:ios:15.1\(2\)sg5:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg6 cpe:2.3:o:cisco:ios:15.1\(2\)sg6:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg7 cpe:2.3:o:cisco:ios:15.1\(2\)sg7:*:*:*:*:*:*:*
cisco ios 15.1\(2\)sg8 cpe:2.3:o:cisco:ios:15.1\(2\)sg8:*:*:*:*:*:*:*
cisco ios 15.2\(1\)e cpe:2.3:o:cisco:ios:15.2\(1\)e:*:*:*:*:*:*:*
cisco ios 15.2\(1\)e1 cpe:2.3:o:cisco:ios:15.2\(1\)e1:*:*:*:*:*:*:*
cisco ios 15.2\(1\)e3 cpe:2.3:o:cisco:ios:15.2\(1\)e3:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e cpe:2.3:o:cisco:ios:15.2\(2\)e:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e1 cpe:2.3:o:cisco:ios:15.2\(2\)e1:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e2 cpe:2.3:o:cisco:ios:15.2\(2\)e2:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e3 cpe:2.3:o:cisco:ios:15.2\(2\)e3:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e4 cpe:2.3:o:cisco:ios:15.2\(2\)e4:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e5 cpe:2.3:o:cisco:ios:15.2\(2\)e5:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e5a cpe:2.3:o:cisco:ios:15.2\(2\)e5a:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e5b cpe:2.3:o:cisco:ios:15.2\(2\)e5b:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e6 cpe:2.3:o:cisco:ios:15.2\(2\)e6:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e7 cpe:2.3:o:cisco:ios:15.2\(2\)e7:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e7b cpe:2.3:o:cisco:ios:15.2\(2\)e7b:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e8 cpe:2.3:o:cisco:ios:15.2\(2\)e8:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e9 cpe:2.3:o:cisco:ios:15.2\(2\)e9:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e9a cpe:2.3:o:cisco:ios:15.2\(2\)e9a:*:*:*:*:*:*:*
cisco ios 15.2\(2\)e10 cpe:2.3:o:cisco:ios:15.2\(2\)e10:*:*:*:*:*:*:*
cisco ios 15.2\(2b\)e cpe:2.3:o:cisco:ios:15.2\(2b\)e:*:*:*:*:*:*:*
cisco ios 15.2\(3\)e cpe:2.3:o:cisco:ios:15.2\(3\)e:*:*:*:*:*:*:*
cisco ios 15.2\(3\)e1 cpe:2.3:o:cisco:ios:15.2\(3\)e1:*:*:*:*:*:*:*
cisco ios 15.2\(3\)e2 cpe:2.3:o:cisco:ios:15.2\(3\)e2:*:*:*:*:*:*:*
cisco ios 15.2\(3\)e3 cpe:2.3:o:cisco:ios:15.2\(3\)e3:*:*:*:*:*:*:*
cisco ios 15.2\(3\)e4 cpe:2.3:o:cisco:ios:15.2\(3\)e4:*:*:*:*:*:*:*
cisco ios 15.2\(3\)e5 cpe:2.3:o:cisco:ios:15.2\(3\)e5:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e cpe:2.3:o:cisco:ios:15.2\(4\)e:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e1 cpe:2.3:o:cisco:ios:15.2\(4\)e1:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e2 cpe:2.3:o:cisco:ios:15.2\(4\)e2:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e3 cpe:2.3:o:cisco:ios:15.2\(4\)e3:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e4 cpe:2.3:o:cisco:ios:15.2\(4\)e4:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e5 cpe:2.3:o:cisco:ios:15.2\(4\)e5:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e5a cpe:2.3:o:cisco:ios:15.2\(4\)e5a:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e6 cpe:2.3:o:cisco:ios:15.2\(4\)e6:*:*:*:*:*:*:*
cisco ios 15.2\(4\)e7 cpe:2.3:o:cisco:ios:15.2\(4\)e7:*:*:*:*:*:*:*

References for CVE-2020-3235

cvelogic Threat Intelligence