Adobe Acrobat and Reader Use-After-Free Vulnerability
CVE-2023-21608 is a security vulnerability in Adobe Acrobat and Reader, added to CISA KEV on October 10, 2023. Patch priority: Plan to patch.
What it is
Adobe Acrobat and Reader contains a use-after-free vulnerability that allows for code execution in the context of the current user.
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 or discontinue use of the product if mitigations are unavailable.
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.
Insurance readiness
Your insurer will ask if this is patched.
Unpatched entries on CISA's Known Exploited Vulnerabilities list are exactly what cyber-insurance carrier questionnaires probe for, and knowing which controls they check is how you keep a renewal from stalling.
Get the free carrier questionnaire →Severity
CVSS base score: 7.8 — HIGH
Weakness classification: CWE-416
CISA due date
Federal deadline: October 31, 2023. 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).
EPSS
EPSS score: 61.5% — higher than 99% of all scored CVEs.
EPSS estimates the probability of exploitation activity in the next 30 days. Every entry on this site is already confirmed exploited, so read it as relative urgency among the things you still have open, not as permission to wait.
Other exploited Adobe Acrobat and Reader entries
More CISA KEV entries for Adobe Acrobat and Reader. Same product line, same actively-exploited status.
Source
This entry comes from CISA's Known Exploited Vulnerabilities catalog, public US-Government data we pull daily. The plain-language framing and the what-to-do guidance above are ours. View the original entry on cisa.gov.
