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Fencer Intel
medium 5.3

CVE-2024-20373 json

Cisco IOS and Cisco IOS XE SNMP Extended ACL Bypass Vulnerability

published last yr. modified 4mo ago also EUVD-2024-18088

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 43%
public exploits
0
none known

Summary

A vulnerability in the implementation of the Simple Network Management Protocol (SNMP) IPv4 access control list (ACL) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to perform SNMP polling of an affected device, even if it is configured to deny SNMP traffic. 

This vulnerability exists because Cisco IOS Software and Cisco IOS XE Software do not support extended IPv4 ACLs for SNMP, but they do allow administrators to configure extended named IPv4 ACLs that are attached to the SNMP server configuration without a warning message. This can result in no ACL being applied to the SNMP listening process. An attacker could exploit this vulnerability by performing SNMP polling of an affected device. A successful exploit could allow the attacker to perform SNMP operations that should be denied. The attacker has no control of the SNMP ACL configuration and would still need a valid SNMP version 2c (SNMPv2c) community string or SNMP version 3 (SNMPv3) user credentials. SNMP with IPv6 ACL configurations is not affected. For more information, see the section of this advisory.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.50% chance of exploitation in the next 30 days, higher than 43% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected products

  • Cisco Cisco IOS XE Catalyst SD-WAN
  • cisco ios_xe_catalyst_sd-wan

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.