# CVE-2026-20311 ## Summary - **CVE ID:** CVE-2026-20311 - **Severity:** MEDIUM - **CVSS Score:** 6.3 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:N/I:N/A:H) - **CWE:** CWE-126 - **Published:** Aug 5, 2026 - **Last Modified:** Aug 5, 2026 ## Description A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient error handling in the web-based management interface. An attacker could exploit this vulnerability by authenticating with a malformed certificate. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. ## Affected Products - Cisco — Cisco IOS XE Software (17.9.7) - Cisco — Cisco IOS XE Software (17.3.1) - Cisco — Cisco IOS XE Software (17.3.1a) - Cisco — Cisco IOS XE Software (17.3.2a) - Cisco — Cisco IOS XE Software (17.3.1w) - Cisco — Cisco IOS XE Software (17.3.2) - Cisco — Cisco IOS XE Software (17.4.1) - Cisco — Cisco IOS XE Software (17.4.1a) - Cisco — Cisco IOS XE Software (17.3.1x) - Cisco — Cisco IOS XE Software (17.3.3) - Cisco — Cisco IOS XE Software (17.5.1) - Cisco — Cisco IOS XE Software (17.4.1b) - Cisco — Cisco IOS XE Software (17.3.1z) - Cisco — Cisco IOS XE Software (17.4.2) - Cisco — Cisco IOS XE Software (17.3.3a) - Cisco — Cisco IOS XE Software (17.3.5) - Cisco — Cisco IOS XE Software (17.3.4) - Cisco — Cisco IOS XE Software (17.5.1a) - Cisco — Cisco IOS XE Software (17.6.1) - Cisco — Cisco IOS XE Software (17.3.4a) - Cisco — Cisco IOS XE Software (17.6.1a) - Cisco — Cisco IOS XE Software (17.7.1) - Cisco — Cisco IOS XE Software (17.6.1x) - Cisco — Cisco IOS XE Software (17.6.2) - Cisco — Cisco IOS XE Software (17.3.4c) - Cisco — Cisco IOS XE Software (17.4.2a) - Cisco — Cisco IOS XE Software (17.3.4b) - Cisco — Cisco IOS XE Software (17.7.1a) - Cisco — Cisco IOS XE Software (17.8.1a) - Cisco — Cisco IOS XE Software (17.6.3a) - Cisco — Cisco IOS XE Software (17.6.3) - Cisco — Cisco IOS XE Software (17.7.2) - Cisco — Cisco IOS XE Software (17.7.1b) - Cisco — Cisco IOS XE Software (17.9.1w) - Cisco — Cisco IOS XE Software (17.3.5a) - Cisco — Cisco IOS XE Software (17.6.1z) - Cisco — Cisco IOS XE Software (17.8.1) - Cisco — Cisco IOS XE Software (17.9.1) - Cisco — Cisco IOS XE Software (17.6.4) - Cisco — Cisco IOS XE Software (17.3.5b) - Cisco — Cisco IOS XE Software (17.9.1a) - Cisco — Cisco IOS XE Software (17.3.6) - Cisco — Cisco IOS XE Software (17.10.1) - Cisco — Cisco IOS XE Software (17.6.1z1) - Cisco — Cisco IOS XE Software (17.10.1a) - Cisco — Cisco IOS XE Software (17.9.2) - Cisco — Cisco IOS XE Software (17.6.5) - Cisco — Cisco IOS XE Software (17.9.1x) - Cisco — Cisco IOS XE Software (17.9.1y) - Cisco — Cisco IOS XE Software (17.3.7) - Cisco — Cisco IOS XE Software (17.9.2a) - Cisco — Cisco IOS XE Software (17.9.3) - Cisco — Cisco IOS XE Software (17.11.1) - Cisco — Cisco IOS XE Software (17.10.1b) - Cisco — Cisco IOS XE Software (17.6.6) - Cisco — Cisco IOS XE Software (17.9.1x1) - Cisco — Cisco IOS XE Software (17.11.1a) - Cisco — Cisco IOS XE Software (17.9.3a) - Cisco — Cisco IOS XE Software (17.12.1) - Cisco — Cisco IOS XE Software (17.3.8) - Cisco — Cisco IOS XE Software (17.9.4) - Cisco — Cisco IOS XE Software (17.12.1w) - Cisco — Cisco IOS XE Software (17.9.1y1) - Cisco — Cisco IOS XE Software (17.12.1a) - Cisco — Cisco IOS XE Software (17.9.5) - Cisco — Cisco IOS XE Software (17.13.1) - Cisco — Cisco IOS XE Software (17.12.1x) - Cisco — Cisco IOS XE Software (17.12.2) - Cisco — Cisco IOS XE Software (17.14.1) - Cisco — Cisco IOS XE Software (17.9.4a) - Cisco — Cisco IOS XE Software (17.3.8a) - Cisco — Cisco IOS XE Software (17.6.6a) - Cisco — Cisco IOS XE Software (17.6.5a) - Cisco — Cisco IOS XE Software (17.6.7) - Cisco — Cisco IOS XE Software (17.15.1) - Cisco — Cisco IOS XE Software (17.13.1a) - Cisco — Cisco IOS XE Software (17.12.2a) - Cisco — Cisco IOS XE Software (17.12.3) - Cisco — Cisco IOS XE Software (17.12.1y) - Cisco — Cisco IOS XE Software (17.12.1z) - Cisco — Cisco IOS XE Software (17.9.5a) - Cisco — Cisco IOS XE Software (17.14.1a) - Cisco — Cisco IOS XE Software (17.9.5b) - Cisco — Cisco IOS XE Software (17.6.8) - Cisco — Cisco IOS XE Software (17.12.4) - Cisco — Cisco IOS XE Software (17.9.6) - Cisco — Cisco IOS XE Software (17.17.1) - Cisco — Cisco IOS XE Software (17.16.1) - Cisco — Cisco IOS XE Software (17.15.1w) - Cisco — Cisco IOS XE Software (17.12.3a) - Cisco — Cisco IOS XE Software (17.9.5c) - Cisco — Cisco IOS XE Software (17.15.1a) - Cisco — Cisco IOS XE Software (17.12.1z1) - Cisco — Cisco IOS XE Software (17.15.2) - Cisco — Cisco IOS XE Software (17.15.1b) - Cisco — Cisco IOS XE Software (17.9.5d) - Cisco — Cisco IOS XE Software (17.15.1x) - Cisco — Cisco IOS XE Software (17.9.6a) - Cisco — Cisco IOS XE Software (17.12.1z2) - Cisco — Cisco IOS XE Software (17.6.8a) - Cisco — Cisco IOS XE Software (17.16.1a) - Cisco — Cisco IOS XE Software (17.15.3) - Cisco — Cisco IOS XE Software (17.12.5) - Cisco — Cisco IOS XE Software (17.15.1y) - Cisco — Cisco IOS XE Software (17.9.5e) - Cisco — Cisco IOS XE Software (17.12.4a) - Cisco — Cisco IOS XE Software (17.15.2a) - Cisco — Cisco IOS XE Software (17.15.2c) - Cisco — Cisco IOS XE Software (17.15.2b) - Cisco — Cisco IOS XE Software (17.12.1z3) - Cisco — Cisco IOS XE Software (17.9.5f) - Cisco — Cisco IOS XE Software (17.12.4b) - Cisco — Cisco IOS XE Software (17.12.5a) - Cisco — Cisco IOS XE Software (17.18.1) - Cisco — Cisco IOS XE Software (17.12.6) - Cisco — Cisco IOS XE Software (17.12.1z4) - Cisco — Cisco IOS XE Software (17.9.8) - Cisco — Cisco IOS XE Software (17.9.7a) - Cisco — Cisco IOS XE Software (17.15.3a) - Cisco — Cisco IOS XE Software (17.15.4) - Cisco — Cisco IOS XE Software (17.12.5b) - Cisco — Cisco IOS XE Software (17.15.3b) - Cisco — Cisco IOS XE Software (17.18.1z) - Cisco — Cisco IOS XE Software (17.9.7b) - Cisco — Cisco IOS XE Software (17.12.5c) - Cisco — Cisco IOS XE Software (26.1.1) - Cisco — Cisco IOS XE Software (17.18.1a) - Cisco — Cisco IOS XE Software (17.15.4a) - Cisco — Cisco IOS XE Software (17.18.2) - Cisco — Cisco IOS XE Software (17.18.1w) - Cisco — Cisco IOS XE Software (17.15.4b) - Cisco — Cisco IOS XE Software (17.12.6a) - Cisco — Cisco IOS XE Software (17.12.7) - Cisco — Cisco IOS XE Software (17.15.4c) - Cisco — Cisco IOS XE Software (17.9.9) - Cisco — Cisco IOS XE Software (17.12.5d) - Cisco — Cisco IOS XE Software (17.15.4s1) - Cisco — Cisco IOS XE Software (17.15.5) - Cisco — Cisco IOS XE Software (17.12.1z5) - Cisco — Cisco IOS XE Software (17.18.1x) - Cisco — Cisco IOS XE Software (17.12.1z6) - Cisco — Cisco IOS XE Software (17.15.4d) - Cisco — Cisco IOS XE Software (17.12.6b) - Cisco — Cisco IOS XE Software (17.4.1c) - Cisco — Cisco IOS XE Software (17.15.5a) - Cisco — Cisco IOS XE Software (17.18.1y) - Cisco — Cisco IOS XE Software (17.12.7a) - Cisco — Cisco IOS XE Software (17.18.3) - Cisco — Cisco IOS XE Software (17.12.7b) - Cisco — Cisco IOS XE Software (17.18.3a) - Cisco — Cisco IOS XE Software (26.1.1a) - Cisco — Cisco IOS XE Software (26.2.1ea) ## References - [CNA](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-xe-webui-dos-PtAODAWW) ## Exploitation Prediction (EPSS) - **EPSS Score:** 0.16% - **EPSS Percentile:** 5.2 --- _Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._