CVE-2021-28550: Adobe Acrobat and Reader Use-After-Free Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 62 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 51.9%
EPSS score, percentile 98.9 of all scored records
- How severe?
- 9.6 Critical
CVSS v3.0 base score, given by the CNA
- What should I do?
CISA deadline . Apply updates per vendor instructions.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Affected
- 2020.001.30020 and earlier
- 2021.001.20150 and earlier
- 2017.011.30194 and earlier
- unspecified
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: .
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Affected | 2020.001.30020 and earlier |
| Affected | 2021.001.20150 and earlier |
| Affected | 2017.011.30194 and earlier |
| Affected | unspecified |
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
Adobe Acrobat and Reader contains a use-after-free vulnerability that could allow an unauthenticated attacker to achieve code execution in the context of the current user.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2021-28550 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Nov 2021.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 17 Nov 2021.
- The CVE record was published on 2 Sep 2021, 62 days before it was added to KEV.
- The CVE record carries a CVSS v3.0 base score of 9.6 (Critical), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 51.9% (percentile 98.9), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
Adobe Acrobat Reader use after free vulnerability could lead to arbitrary code execution
Acrobat Reader DC versions versions 2021.001.20150 (and earlier), 2020.001.30020 (and earlier) and 2017.011.30194 (and earlier) are affected by a Use After Free 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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
More exploited Adobe vulnerabilities
- CVE-2026-48356: Adobe Commerce and Magento Unrestricted Upload of File with Dangerous Type Vulnerability
- CVE-2026-71362: Adobe Commerce and Magento Incorrect Authorization Vulnerability
- CVE-2026-75650: Adobe Commerce and Magento Improper Neutralization of Special Elements Used in a Template Engine Vulnerability
- CVE-2026-48282: Adobe ColdFusion Path Traversal Vulnerability
- CVE-2009-3459: Adobe Acrobat and Reader Heap-Based Buffer Overflow Vulnerability
- CVE-2020-9715: Adobe Acrobat Use-After-Free Vulnerability