Use‑After‑Free RCE in Adobe Acrobat Reader DC (CVE‑2026‑79909) Threatens Endpoint Users

Use‑After‑Free RCE in Adobe Acrobat Reader DC (CVE‑2026‑79909) Threatens Endpoint Users

What It Is – A use‑after‑free flaw in the handling of Report objects allows an attacker who convinces a user to open a malicious PDF or visit a crafted web page to execute arbitrary code in the context of the Acrobat Reader process.

Exploitability – The vulnerability is rated CVSS 7.8 (High). Exploitation requires user interaction (malicious file or page) but no additional privileges; a proof‑of‑concept has been publicly disclosed.

Affected Products – Adobe Acrobat Reader DC (all supported versions prior to the September 2026 security update).

Why It Matters for Trust & Control Assurance

• Vulnerability Management – Demonstrates the need for continuous monitoring of endpoint software inventories and timely patch deployment to satisfy the control objective of maintaining a robust vulnerability‑remediation process.
• Audit Evidence – Organizations must retain verifiable evidence (e.g., patch‑install logs, configuration baselines) that the Adobe update was applied across all workstations, supporting audit readiness for frameworks that map to this control.
• Defensible Risk Posture – Failure to remediate a high‑severity RCE can erode stakeholder trust; a documented, automated patch‑management program provides a defensible posture during security reviews.

Recommended Actions

1. Deploy Adobe’s September 2026 security update (APS‑B26‑141) to all Acrobat Reader DC installations immediately.
2. Verify patch levels via an endpoint‑management tool and retain logs as proof of remediation.
3. Enable automatic updates in Acrobat Reader to reduce future exposure.
4. Update your asset inventory to flag any legacy versions still in use and prioritize their remediation.
5. Incorporate this CVE into your vulnerability‑scanning ruleset and monitor for exploitation attempts.

Source: Zero Day Initiative advisory – ZDI‑26‑665