Adobe Acrobat and Reader Prototype Pollution Vulnerability
What it is
Adobe Acrobat and Reader contain a prototype pollution vulnerability that allows for arbitrary code execution.
Who's affected
Affects anyone opening, editing, or signing PDFs in Adobe Acrobat or Reader. For a CPA or legal practice, PDFs are typically client tax returns, engagement letters, signed agreements, and discovery documents — opening a malicious PDF runs attacker code in the user's session, which can pivot to file shares or email.
What to do
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA action deadline: April 27, 2026. Federal agencies must complete the required action by this date. For private SMBs the deadline is advisory — but treat it as a strong recommendation, especially if you handle regulated data (HIPAA, GLBA, ABA model rules).
If you don't have someone in-house to verify the patch deployed across every endpoint — or you're not sure whether you're affected — that's exactly the kind of triage we do. Book a free 20-minute triage call.
Severity
CVSS base score: 8.6 — HIGH
Weakness classification: CWE-1321
Source
Pulled daily from the public cisagov/kev-data mirror (CC0). View the original entry on cisa.gov. CISA KEV is US-Government public-domain data; we add the SMB-vertical framing and the coping action above.