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CVE-2021-39855

6.5 · MEDIUM

Acrobat Reader DC ActiveX Control versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an Information Disclosure vulnerability.

Published Sep 29, 2021CWE-200EPSS 2.36%

Overview

CVE-2021-39855 is a medium-severity vulnerability. It was published on September 29, 2021 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

Acrobat Reader DC ActiveX Control versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by an Information Disclosure vulnerability. An unauthenticated attacker could leverage this vulnerability to obtain NTLMv2 credentials. Exploitation of this issue requires user interaction in that a victim must open a maliciously crafted Microsoft Office file, or visit an attacker controlled web page.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refhelpx.adobe.com/security/products/acrobat/apsb21-55.htmlRefhelpx.adobe.com/security/products/acrobat/apsb21-55.html

How CyberStrike helps

Frequently asked questions

What is CVE-2021-39855?

CVE-2021-39855 is a medium-severity vulnerability. It was published on September 29, 2021 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2021-39855?

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-39855?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-39855?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-39855 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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