What is CVE-2021-21034?

CVE-2021-21034 is a medium-severity vulnerability in Adobe Acrobat, classified under Out-of-bounds Read. CVSS score: 4.3/10. Published 2021-02-11.

How severe is CVE-2021-21034?

Medium severity. CVSS v3 base score is 4.3 out of 10.

Out-of-bounds Read in Adobe Acrobat

CVE-2021-21034

Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by an Out-of-bounds Read vulnerability. An unauthenticated attacker could leverage this vulnerability to locally elevate privileges in the context of the current user. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

Vulnerability class: Buffer Overflow

Published 2021-02-11 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.026 (84.6th percentile), scored 2026-10-02.

Low probability of exploitation in the next 30 days, but still tracked. 85th percentile — 84.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.026 · newest: 0.026 · change: 0.000

Affected products

Adobe Acrobat
Adobe Acrobat Dc
Adobe Acrobat Reader — versions unspecified
Adobe Acrobat Reader
Adobe Acrobat Reader Dc
Apple macOS
Microsoft Windows

Weakness classification (CWE)

CWE-125 — Out-of-bounds Read

References

helpx.adobe.com/security/products/acrobat/apsb21-09.html (Vendor Advisory)

Frequently asked questions

What is CVE-2021-21034?: CVE-2021-21034 is a medium-severity vulnerability in Adobe Acrobat, classified under Out-of-bounds Read. CVSS score: 4.3/10. Published 2021-02-11.
How severe is CVE-2021-21034?: Medium severity. CVSS v3 base score is 4.3 out of 10.