CVE-2026-20124
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.
Key facts
- CVSS score
- 7.7 (v3.1)
- Severity
- HIGH
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H- Weakness (CWE)
- CWE-772
- EPSS score
- 0.5% (41th percentile)
- In CISA KEV
- No
- In EU EUVD
- Yes (EUVD-2026-53449)
- Published
- August 5, 2026
- NVD last modified
- September 17, 2026
- Status
- Analyzed
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2026-53449 in the EU Vulnerability Database. Last updated in EUVD on August 5, 2026.
View on the EU Vulnerability DatabaseAffected products
- cisco / ios xe
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and 227 more…
Certified products that may be affected
12 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.
- Cisco Embedded Services 9300 and 3300 Series Switches (ESS9300 & ESS3300) running IOS-XE 17.15 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-11662-2026 - active
- Cisco Catalyst 8000V Edge (C8000V) running IOS-XE 17.15 - Cisco Systems, Inc. - Common Criteria Certificate Number: 2025/161 - active
- Cisco 1000 Series Integrated Services Routers (C1100), Cisco Catalyst IR1800 Rugged Series Routers (IR1800), Cisco Catalyst IR8300 Rugged Series Routers (IR8300) running IOS-XE 17.15 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-11643-2025 - active
- Cisco Catalyst Industrial Ethernet 9300 Rugged Series Switches running IOS-XE 17.15 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-11603-2025 - active
- Cisco Aggregation Services Router 1000 Series (ASR1K), Cisco Catalyst 8200, 8300, 8500 Series Edge Routers (Cat8K) running IOS-XE version 17.15 - Cisco Systems, Inc. - Common Criteria CCEVS-VR-VID-11642-2025 - active
See all 12 in the Security Certifications Explorer.
References
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-iosxe-snmp-dos-ZAqNm4MD(Mitigation, Vendor Advisory)
Last updated September 19, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
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