Vulnerability in Cisco iOS Xe Software
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.005 (42.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 42.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
- Cisco iOS Xe Software — versions 17.2.1a, 3.18.7SP, 16.12.1y
- Cisco iOS Xe — versions 16.10.1, 16.10.1a, 16.10.1b
Weakness classification (CWE)
References
- sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-… (Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-20124?
- CVE-2026-20124 is a high-severity vulnerability in Cisco iOS Xe Software, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 7.7/10. Published 2026-08-05.
- How severe is CVE-2026-20124?
- High severity. CVSS v3 base score is 7.7 out of 10.