What is the CVSS score of CVE-2020-21523?

CVE-2020-21523 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.6%.

Is there a public PoC exploit available for CVE-2020-21523?

Yes, a public proof-of-concept exploit is available for CVE-2020-21523. Prioritise patching immediately. EPSS: 2.6%.

Halo CVE-2020-21523

CRITICAL

Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') (CWE-74)

2020-09-30 cve@mitre.org

RCE Halo

9.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

9.8 CRITICAL

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

CVE Published

Sep 30, 2020 - 18:15 nvd

CRITICAL 9.8

DescriptionNVD

A Server-Side Freemarker template injection vulnerability in halo CMS v1.1.3 In the Edit Theme File function. The ftl file can be edited. This is the Freemarker template file. This file can cause arbitrary code execution when it is rendered in the background. exp: <#assign test="freemarker.template.utility.Execute"?new()> ${test("touch /tmp/freemarkerPwned")}

AnalysisAI

A Server-Side Freemarker template injection vulnerability in halo CMS v1.1.3 In the Edit Theme File function. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.

Technical ContextAI

This vulnerability is classified under CWE-74. A Server-Side Freemarker template injection vulnerability in halo CMS v1.1.3 In the Edit Theme File function. The ftl file can be edited. This is the Freemarker template file. This file can cause arbitrary code execution when it is rendered in the background. exp: <#assign test="freemarker.template.utility.Execute"?new()> ${test("touch /tmp/freemarkerPwned")} Affected products include: Halo.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.