HighAdvisoryCisco PSIRT — security advisories· 25 Mar 2026

Cisco IOS Software and IOS XE Software Release 3E HTTP Server Denial of Service Vulnerability

Severity: High · Kind: Advisory

Plain-English summary on the way

We've ingested this item but haven't summarised it yet. Read the upstream advisory using the link below in the meantime — the AI summary will appear here once the next run completes.

From the source

A vulnerability in the HTTP Server feature of Cisco IOS Software and Cisco IOS XE Software Release 3E could allow an authenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending malformed HTTP requests to an affected device. A successful exploit could allow the attacker to cause a watchdog timer to expire and the device to reload, resulting in a DoS condition. To exploit this vulnerability, the attacker must have a valid user account. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-http-dos-sbv8XRpL This advisory is part of the March 2026 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2026 Semiannual Cisco IOS and IOS XE Software Security Advisory Bundled Publication . <br/>Security Impact Rating: High <br/>CVE: CVE-2026-20125

Was this useful?

00000Sign in to react

Plain-English summaries are AI-generated and reviewed for tone, not technical accuracy. For incident response, always rely on the original source linked above.