Description
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.
Published: 2026-03-25
Score: 7.7 High
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service via device reload
Action: Immediate Patch
AI Analysis

Impact

An improper validation of user‑supplied input in the HTTP Server feature of Cisco IOS Software and IOS XE Software Release 3E allows an attacker who can authenticate to a device to send malicious HTTP requests that trigger a watchdog timer expiry and force the device to reload. The reload terminates all services, producing a denial‑of‑service impact on availability.

Affected Systems

Any Cisco IOS Software or Cisco IOS XE Software device running Release 3E with the HTTP Server feature enabled is affected. An authenticated attacker can bring the device offline through this vulnerability.

Risk and Exploitability

The CVSS score of 7.7 indicates high severity, and the lack of an EPSS score and absence from the KEV catalog suggest limited public exploitation. Attacks require valid credentials, but once authenticated the attacker can construct and send malformed HTTP requests to trigger the reload. Prompt patching is advised to maintain service availability.

Generated by OpenCVE AI on March 25, 2026 at 19:55 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the latest Cisco IOS or IOS XE firmware that includes the fix for this vulnerability.
  • Verify that the device is running the patched release and that the HTTP Server feature operates correctly.
  • If patching cannot occur immediately, restrict HTTP Server access to trusted networks or disable the feature until a fix is available.

Generated by OpenCVE AI on March 25, 2026 at 19:55 UTC.

Tracking

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Advisories

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History

Thu, 26 Mar 2026 12:00:00 +0000

Type Values Removed Values Added
First Time appeared Cisco
Cisco ios
Cisco ios Xe Software
Vendors & Products Cisco
Cisco ios
Cisco ios Xe Software

Wed, 25 Mar 2026 22:00:00 +0000

Type Values Removed Values Added
Title Authenticated HTTP Server Exploit Causing Device Reload and Denial of Service

Wed, 25 Mar 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Wed, 25 Mar 2026 16:15:00 +0000

Type Values Removed Values Added
Description 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.
Weaknesses CWE-228
References
Metrics cvssV3_1

{'score': 7.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H'}

Subscriptions

Cisco Ios Ios Xe Software
cve-icon MITRE

Status: PUBLISHED

Assigner: cisco

Published:

Updated: 2026-03-25T17:52:07.963Z

Reserved: 2025-10-08T11:59:15.378Z

Link: CVE-2026-20125

cve-icon Vulnrichment

Updated: 2026-03-25T17:52:04.380Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-03-25T16:16:16.750

Modified: 2026-03-26T15:13:15.790

Link: CVE-2026-20125

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-03-26T11:42:47Z

Weaknesses