CVE-2021-21265

Name: CVE-2021-21265
Creator: NVD / NIST
Published: 2021-03-10T22:15:12.057+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.51%

Last modified Jun 17, 2026

CVE-2021-21265 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 1.51% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

1.51%

71.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-644

Affected Software

Vendor	Product	Versions
Octobercms	October	< 1.1.2

References

https://github.com/octobercms/library/commit/f29865ae3db7a03be7c49294cd93980ec457f10d
https://github.com/octobercms/library/commit/f86fcbcd066d6f8b939e8fe897409d152b11c3c6Patch, Third Party Advisory
https://github.com/octobercms/october/commit/555ab61f2313f45d7d5d138656420ead536c5d30
https://github.com/octobercms/october/commit/f638d3f78cfe91d7f6658820f9d5e424306a3db0Patch, Third Party Advisory
https://github.com/octobercms/october/security/advisories/GHSA-xhfx-hgmf-v6vpPatch, Third Party Advisory
https://packagist.org/packages/october/backend
https://github.com/octobercms/library/commit/f86fcbcd066d6f8b939e8fe897409d152b11c3c6Patch, Third Party Advisory
https://github.com/octobercms/october/commit/f638d3f78cfe91d7f6658820f9d5e424306a3db0Patch, Third Party Advisory
https://github.com/octobercms/october/security/advisories/GHSA-xhfx-hgmf-v6vpPatch, Third Party Advisory

Timeline

Published: Mar 10, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-21265?

How severe is CVE-2021-21265?

CVE-2021-21265 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.51% probability of exploitation in the next 30 days.

How do I fix CVE-2021-21265?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-21265?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST