CVE-2021-21017
HighExploitedPublic exploitAcrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by a heap-based buffer overflow vulnerability.
Published Feb 11, 2021 · Updated Oct 23, 2025
Key Facts
Patch immediately- CVE-2021-21017 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Acrobat (Adobe), Acrobat Dc (Adobe), Acrobat Reader (Adobe) and 1 more product.
- It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Feb 9, 2021. Public exploit code is available.
- EPSS estimates a 86% probability of exploitation in the next 30 days.
- Fixed versions are available, including Acrobat <=17.011.30188, Acrobat Dc <=20.013.20074, Acrobat Reader <=17.011.30188.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
86%
Higher than 99.7% of all scored CVEs
Exploited in the wild
Yes
4 catalog listings
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2021-21017 brief as a PDF
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Description
Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by a heap-based buffer overflow vulnerability. 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.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| CISA KEV | Nov 3, 2021 | Nov 17, 2021 | Not reported |
| Industry KEV feed | Feb 9, 2021 | Nov 17, 2021 | Not reported |
| CIRCL KEV | Nov 3, 2021 | Nov 17, 2021 | Not reported |
| ENISA EUVD | Nov 3, 2021 | n/a | Not reported |
Required action: Apply updates per vendor instructions.
Affected Products
5 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| AcrobatAdobe | See advisory | 17.011.30188 |
| Acrobat DcAdobe | See advisory | 20.013.20074 |
| Acrobat ReaderAdobe | >= unspecified | 17.011.30188 |
| Acrobat Reader DcAdobe | See advisory | 20.013.20074 |
Patched Releases
Acrobat
<=17.011.30188
Acrobat Dc
<=20.013.20074
Acrobat Reader
<=17.011.30188
Acrobat Reader Dc
<=20.013.20074
Timeline
Added to Industry KEV feed
Feb 9, 2021
Publicly disclosed
Feb 11, 2021
Added to CISA KEV
Nov 3, 2021
Added to CIRCL KEV
Nov 3, 2021
Added to ENISA EUVD
Nov 3, 2021
Last updated
Oct 23, 2025
Weakness Type
- CWE-122 Heap-based Buffer Overflow
- CWE-787 Out-of-bounds Write
References
FAQ
Common Questions.
Acrobat Reader DC versions versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by a heap-based buffer overflow vulnerability.
Affected: Acrobat (Adobe); Acrobat Dc (Adobe); Acrobat Reader (Adobe) versions >= unspecified, among others. The full list is in the CVE brief.
It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Feb 9, 2021.
Yes. It was added on Nov 3, 2021 with a federal remediation due date of Nov 17, 2021.
Public exploit code is available.
Fixed versions are available, including Acrobat <=17.011.30188, Acrobat Dc <=20.013.20074, Acrobat Reader <=17.011.30188.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
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