Is CVE-2021-21265 actively exploited?

CVE-2021-21265 has no public evidence of in-the-wild exploitation as of 2025-05-30.

What is the CVSS score for CVE-2021-21265?

CVE-2021-21265 has a CVSS score of 6.8 (MEDIUM severity). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N.

How do I patch CVE-2021-21265?

Patch guidance is available from octobercms security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2021-21265.

CVE-2021-21265 - remediation guidance & executive summary

Description

October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. In October before version 1.1.2, when running on poorly configured servers (i.e. the server routes any request, regardless of the HOST header to an October CMS instance) the potential exists for Host Header Poisoning attacks to succeed. This has been addressed in version 1.1.2 by adding a feature to allow a set of trusted hosts to be specified in the application. As a workaround one may set the configuration setting cms.linkPolicy to force.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N
Attack Vector: network
Complexity: high
Privileges: none
User Action: none
Scope: changed
Confidentiality: none
Integrity: high
Availability: none
Weaknesses: CWE-644

Metadata

Primary Vendor: OCTOBERCMS
Published: 3/10/2021
Last Modified: 5/30/2025
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

CVE-2021-21265

Description

CVSS Metrics

Metadata

Affected Products

Remediation Guidance

Executive Summary