CVE-2021-39863

Name: CVE-2021-39863
Creator: NVD / NIST
Published: 2021-09-29T16:15:11.19+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 12.50%

Last modified Jun 17, 2026

CVE-2021-39863 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. Acrobat Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by a Buffer Overflow vulnerability when parsing a specially crafted PDF file. An unauthenticated attacker could leverage this vulnerability to achieve arbitrary code execution in the context of the current user. EPSS estimates a 12.50% chance of exploitation in the next 30 days.

Description

Acrobat Reader DC versions 2021.005.20060 (and earlier), 2020.004.30006 (and earlier) and 2017.011.30199 (and earlier) are affected by a Buffer Overflow vulnerability when parsing a specially crafted PDF file. An unauthenticated attacker could leverage this vulnerability to achieve arbitrary code execution in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

12.50%

95.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-122

Affected Software

Vendor	Product	Versions
Adobe	Acrobat Dc	>= 15.008.20082, <= 21.005.20060
Adobe	Acrobat Dc	>= 15.008.20082, <= 21.005.20058
Adobe	Acrobat Reader Dc	>= 15.008.20082, <= 21.005.20060
Adobe	Acrobat	>= 20.001.30005, <= 20.004.30006
Adobe	Acrobat Reader	>= 20.001.30005, <= 20.004.30006
Adobe	Acrobat 2017	>= 17.011.30059, <= 17.011.30199
Adobe	Acrobat Reader 2017	>= 17.011.30059, <= 17.011.30199

References

https://helpx.adobe.com/security/products/acrobat/apsb21-55.htmlRelease Notes, Vendor Advisory
https://helpx.adobe.com/security/products/acrobat/apsb21-55.htmlRelease Notes, Vendor Advisory

Timeline

Published: Sep 29, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-39863?

How severe is CVE-2021-39863?

CVE-2021-39863 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 12.50% probability of exploitation in the next 30 days.

How do I fix CVE-2021-39863?

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-2021-39863?

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

Scan your code now

Source: NVD / NIST