Is CVE-2021-21265 in the CISA KEV catalog?

No. CVE-2021-21265 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-21265?

CVE-2021-21265 has a CVSS v3 base score of 6.8 (MEDIUM).

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

CVE-2021-21265 has an EPSS score of 1.51% (71th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-21265?

Upgrade october to 1.1.2 or later.

CVE & CISA-KEV Catalog

CVE-2021-21265

MEDIUMEPSS 71th pctl

6.8

CVSS v3

NVD

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.

CWE-644

How to fix

Remediation Available

octoberNVD

Affected:< 1.1.2Fixed in:1.1.2CVE-2021-21265derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeChanged

Impact

ConfidentialityNone

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

1.51%probability of exploitation in 30 days

71stpercentile

Elevated risk: more likely to be exploited than 71% of all known CVEs.

References

Patch3

Other references3

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-05-30.