CVE-2021-28550
Published: November 3, 2021
Official Description
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.
CISA KEV Advisory
Adobe Acrobat and Reader Use-After-Free 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.
Apply updates per vendor instructions.
Risk Analysis
This CVE describes a use-after-free vulnerability in Adobe Acrobat and Reader that could allow an unauthenticated attacker to achieve code execution. This execution would occur in the context of the current user. The high EPSS score of 0.32051 and its inclusion in CISA's KEV catalog indicate a significant and confirmed exploitation risk.
This vulnerability is being actively exploited in the wild and is listed in CISA's KEV catalog, confirming its active use by threat actors. Such flaws are typically exploited by tricking a user into opening a malicious PDF document.
Users should update Adobe Acrobat and Reader to the latest patched versions immediately. Exercise caution when opening PDF files from untrusted sources.
Technical Analysis
CVE-2021-28550 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-28550 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (1)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-28550 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1