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VULNERABILITY BRIEF 🟠 High Vulnerability

Local Privilege Escalation in Foxit PDF Reader (CVE‑2026‑91813) via FoxitUpdater Race Condition

A race‑condition bug in Foxit PDF Reader’s updater lets a low‑privileged attacker gain SYSTEM rights. The flaw (CVE‑2026‑91813, CVSS 7.8) is patched by Foxit, underscoring the need for auditable patch‑management and least‑privilege controls for compliance readiness.

Verisq™ Intelligence · 📅 September 26, 2026 · 📰 zerodayinitiative.com
🟠
Severity
High
VU
Type
Vulnerability
🎯
Confidence
High
🏢
Affected
1 sector(s)
✅
Actions
3 recommended
📰
Source
zerodayinitiative.com

Local Privilege Escalation in Foxit PDF Reader (CVE‑2026‑91813) via FoxitUpdater Race Condition

What It Is – A race‑condition flaw in the FoxitUpdater component of Foxit PDF Reader allows a low‑privileged attacker who can run code on a workstation to obtain SYSTEM‑level privileges.

Exploitability – The vulnerability is locally exploitable; an attacker must first achieve code execution as a standard user. CVSS 7.8 (AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). No public exploits are known, but the attack path is straightforward once foothold is gained.

Affected Products – Foxit PDF Reader (any version prior to the September 2026 security update).

Why It Matters for Trust & Control Assurance

  • Patch & Vulnerability Management – Demonstrates the need for continuous, auditable patching processes; a missed update creates a high‑impact privilege‑escalation gap.
  • Least‑Privilege Controls – Highlights the importance of enforcing least‑privilege on endpoint software and verifying that update mechanisms cannot be abused.
  • Defensible Evidence – Timely remediation provides concrete evidence for auditors that the organization maintains an effective control‑assurance posture.

Recommended Actions

  1. Deploy Foxit’s September 2026 security update to all endpoints immediately.
  2. Verify the patch resolves the race‑condition through internal testing or vendor validation.
  3. Record the remediation in your patch‑management system and retain proof for audit trails.

Source: Zero Day Initiative Advisory – ZDI‑26‑742

📰 Original Source
http://www.zerodayinitiative.com/advisories/ZDI-26-742/ ↗

This Verisq Intelligence Brief is an independent analysis. Read the original reporting at the link above.

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