CVE-2026-20311

Medium

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.

SeverityMedium
CVSS6.3
Exploit probability—
ProductCisco IOS XE Software
PublishedAug 5, 2026
First seenAug 5, 2026
Weakness typeCWE-126CWE-126

How to fix

Sources list no fixed version or patch link for this vulnerability.

Affected products

ProductAffected versionsFixed in
Cisco Cisco IOS XE Software17.3.1, 17.3.1a, 17.3.2a, 17.3.1w, 17.3.2, 17.4.1, 17.4.1a, 17.3.1x, 17.3.3, 17.5.1, 17.4.1b, 17.3.1z, 17.4.2, 17.3.3a, 17.3.5, 17.3.4, 17.5.1a, 17.6.1, 17.3.4a, 17.6.1a, 17.7.1, 17.6.1x, 17.6.2, 17.3.4c, 17.4.2a, 17.3.4b, 17.7.1a, 17.8.1a, 17.6.3a, 17.6.3, 17.7.2, 17.7.1b, 17.9.1w, 17.3.5a, 17.6.1z, 17.8.1, 17.9.1, 17.6.4, 17.3.5b, 17.9.1a, 17.3.6, 17.10.1, 17.6.1z1, 17.10.1a, 17.9.2, 17.6.5, 17.9.1x, 17.9.1y, 17.3.7, 17.9.2a, 17.9.3, 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, 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, 17.15.1, 17.13.1a, 17.12.2a, 17.12.3, 17.12.1y, 17.12.1z, 17.9.5a, 17.14.1a, 17.9.5b, 17.6.8, 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, 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, 17.18.1z, 17.9.7b, 17.12.5c, 26.1.1, 17.18.1a, 17.15.4a, 17.18.2, 17.18.1w, 17.15.4b, 17.12.6a, 17.12.7, 17.15.4c, 17.9.9, 17.12.5d, 17.15.4s1, 17.15.5, 17.12.1z5, 17.18.1x, 17.12.1z6, 17.15.4d, 17.12.6b, 17.4.1c, 17.15.5a, 17.18.1y, 17.12.7a, 17.18.3, 17.12.7b, 17.18.3a, 26.1.1a, 26.2.1ea—

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