🔐 CVE Alert

CVE-2026-20124

HIGH 7.7

Cisco IOS XE Software SNMP Denial of Service Vulnerability

CVSS Score
7.7
EPSS Score
0.0%
EPSS Percentile
0th

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to improper error handling when parsing SNMP requests. This vulnerability affects all versions of SNMP — Versions 1, 2c, and 3. An attacker could exploit this vulnerability by sending a malformed SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly. The attacker must have the SNMPv1 or v2c read-only or read-write community string or valid SNMPv3 user credentials on the affected device.

CWE CWE-772
Vendor cisco
Product cisco ios xe software
Ecosystems
Industries
NetworkingTelecommunications
Published Aug 5, 2026
Last Updated Aug 5, 2026
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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
Attack Vector
Network
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
High

Affected Versions

Cisco / Cisco IOS XE Software
17.2.1a 3.18.7SP 16.12.1y 16.12.3s 16.7.1b 16.6.2 16.6.5 16.12.1w 3.18.4S 16.9.1d 17.3.1 16.9.4c 16.7.1 17.2.1 16.6.8 16.9.1b 3.16.8S 16.9.2s 16.12.4 16.12.3a 17.1.1s 16.11.1a 16.7.2 16.11.1b 16.9.1s 16.9.3h 16.9.1c 16.6.5a 16.6.3 16.10.1f 17.2.1v 16.8.1e 16.9.3a 16.12.1a 16.12.1x 3.16.10aS 16.6.4s 16.10.1c 16.12.3 16.11.2 16.6.5b 16.12.2s 16.10.1b 16.7.3 16.6.7 16.9.6 16.9.2 3.16.10S 16.10.1 16.12.1t 3.18.3bSP 3.13.9S 3.18.3aSP 3.18.5SP 16.9.1 16.8.1a 3.18.8aSP 16.9.3s 16.6.7a 16.12.2 16.11.1 16.9.3 16.11.1s 16.12.1 3.16.9S 17.1.1 17.1.2 16.10.1d 17.1.1t 16.9.4 16.8.3 16.12.2t 16.9.5 3.16.7S 16.8.1s 16.10.1e 16.8.2 16.6.4 16.8.1b 16.10.1a 16.12.1z 16.8.1c 16.9.1a 3.16.7aS 16.9.5f 16.6.4a 16.10.1g 3.13.10S 16.8.1 16.6.6 16.9.2a 16.8.1d 16.10.3 3.18.4SP 3.18.6SP 3.18.3SP 16.7.1a 16.11.1c 16.10.1s 17.2.1r 3.16.7bS 17.1.1a 16.10.2 16.12.2a 3.16.6bS 16.12.1c 16.12.1s 16.7.4 3.18.9SP 17.2.2 16.9.8 16.9.7 17.1.3 17.3.1a 17.3.2a 16.12.5 17.3.1w 17.3.2 17.4.1 16.12.4a 17.4.1a 3.16.10bS 17.3.1x 17.3.3 16.6.9 17.2.3 17.5.1 16.12.1z1 16.12.5a 17.4.1b 17.3.1z 16.12.5b 17.4.2 17.3.3a 17.3.5 17.3.4 17.5.1a 16.12.6 17.6.1 16.12.1z2 16.6.10 17.3.4a 17.6.1a 17.7.1 17.6.1x 17.6.2 16.12.6a 17.3.4c 17.4.2a 17.3.4b 17.7.1a 16.12.7 17.8.1a 17.6.3a 17.6.3 17.7.2 17.7.1b 17.9.1w 17.3.5a 17.6.1z 16.12.8 17.8.1 17.9.1 17.6.4 17.3.5b 17.9.1a 17.3.6 17.10.1 16.9.8a 17.6.1z1 17.10.1a 17.9.2 17.6.5 17.9.1x 17.9.1y 16.9.8b 17.3.7 17.9.2a 17.9.3 16.12.9 17.11.1 17.10.1b 17.6.6 17.9.1x1 17.11.1a 17.9.3a 17.12.1 17.3.8 17.9.4 16.12.10 17.12.1w 17.9.1y1 17.12.1a 17.9.5 17.13.1 17.12.1x 17.12.2 17.14.1 17.9.4a 17.3.8a 17.6.6a 17.6.5a 17.6.7 16.12.10a 17.15.1 17.13.1a 17.12.2a 16.12.11 17.12.3 17.12.1y 17.12.1z 17.9.5a 17.14.1a 17.9.5b 17.6.8 16.12.12 17.12.4 17.9.6 17.17.1 17.16.1 17.15.1w 17.12.3a 17.9.5c 17.15.1a 17.12.1z1 17.15.2 17.15.1b 17.9.5d 17.15.1x 17.9.6a 17.12.1z2 17.6.8a 17.16.1a 16.12.13 17.15.3 17.9.7 17.12.5 17.15.1y 17.9.5e 17.12.4a 17.15.2a 17.15.2c 17.15.2b 17.12.1z3 17.9.5f 17.12.4b 17.12.5a 17.18.1 17.12.6 17.12.1z4 17.9.8 17.9.7a 17.15.3a 17.15.4 17.12.5b 17.15.3b 16.12.14 17.9.7b 17.12.5c 17.18.1a 17.15.4a 17.18.2 17.18.1w 17.15.4b 17.12.6a 17.15.4c 17.9.9 17.12.5d 16.12.15 17.15.4s1 17.12.1z5 17.18.1x 17.12.1z6 17.15.4d 17.12.6b 17.4.1c 17.18.1y

References

NVD ↗ CVE.org ↗ EPSS Data ↗
sec.cloudapps.cisco.com: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-snmp-dos-ZAqNm4MD