CVE-2025-69627: Nitro PDF Pro Use-After-Free Vulnerability

CVE-2025-69627 Overview

CVE-2025-69627 is a heap use-after-free vulnerability in Nitro PDF Pro for Windows version 14.41.1.4. The vulnerability exists in the implementation of the JavaScript method this.mailDoc(). During execution, an internal XID object is allocated and then freed prematurely, after which the freed pointer is still passed into UI and logging helper functions. Because the freed memory region may contain unpredictable heap data or remnants of attacker-controlled JavaScript strings, downstream routines such as wcscmp() may process invalid or stale pointers. This can result in access violations and non-deterministic crashes.

Critical Impact

This use-after-free vulnerability could allow an attacker to achieve arbitrary code execution or cause application crashes by exploiting heap memory corruption through malicious PDF documents containing crafted JavaScript.

Affected Products

• Nitro PDF Pro for Windows 14.41.1.4

Discovery Timeline

• April 13, 2026 - CVE-2025-69627 published to NVD
• April 14, 2026 - Last updated in NVD database

Technical Details for CVE-2025-69627

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption flaw that occurs when a program continues to use a pointer after the memory it references has been freed. In the context of Nitro PDF Pro, the vulnerability manifests within the JavaScript API implementation, specifically in the this.mailDoc() method used for email functionality within PDF documents.

The core issue stems from improper memory management of an internal XID object. When the mailDoc() function executes, it allocates heap memory for the XID object, then prematurely frees this memory while still maintaining a reference to it. Subsequent operations pass this dangling pointer to UI display and logging helper functions, which attempt to access the now-invalid memory region.

Root Cause

The root cause is a memory lifecycle management error in the mailDoc() JavaScript method implementation. The XID object is freed before all references to it are eliminated, creating a dangling pointer condition. When this freed memory is subsequently accessed by functions like wcscmp(), the application attempts to read data from an invalid memory location. The freed heap region may have been reallocated for other purposes or may contain remnants of previous allocations, including potentially attacker-controlled JavaScript string data.

Attack Vector

This vulnerability requires local access to exploit. An attacker would need to craft a malicious PDF document containing JavaScript code that invokes the vulnerable this.mailDoc() method. When a victim opens this PDF in Nitro PDF Pro, the JavaScript executes, triggering the use-after-free condition.

The attack scenario typically involves:

1. An attacker creates a specially crafted PDF with embedded JavaScript calling mailDoc()
2. The victim opens the malicious PDF in Nitro PDF Pro for Windows 14.41.1.4
3. The JavaScript execution triggers the memory corruption through the dangling pointer
4. The attacker may achieve code execution if they can control the heap layout to place malicious data in the freed memory region

The vulnerability mechanism involves the premature freeing of the XID object followed by continued use of its pointer in UI and logging functions. When wcscmp() or similar string comparison routines process the stale pointer, they may read attacker-controlled data from the heap, potentially leading to arbitrary code execution or application crashes. For detailed technical analysis, refer to the Jeroscope Security Advisory 2025.

Detection Methods for CVE-2025-69627

Indicators of Compromise

• Unexpected crashes of Nitro PDF Pro when opening PDF documents with embedded JavaScript
• Access violation errors or heap corruption warnings in Windows Event logs associated with Nitro PDF Pro processes
• PDF documents with obfuscated JavaScript containing calls to mailDoc() method
• Unusual process behavior or child process spawning from Nitro PDF Pro after opening PDF files

Detection Strategies

• Monitor for Nitro PDF Pro process crashes with exception codes indicating heap corruption (e.g., 0xC0000005 access violation)
• Implement endpoint detection rules to flag PDF documents containing JavaScript with mailDoc() method calls
• Deploy behavioral analysis to detect suspicious memory access patterns in Nitro PDF Pro processes
• Use application whitelisting to control which PDF documents can execute JavaScript in enterprise environments

Monitoring Recommendations

• Enable crash dump collection for Nitro PDF Pro to capture forensic data on exploitation attempts
• Configure SentinelOne endpoint protection to monitor PDF reader processes for anomalous memory operations
• Implement network-level scanning for PDF documents containing embedded JavaScript before delivery to endpoints
• Establish baseline behavior for Nitro PDF Pro and alert on deviations that may indicate exploitation

How to Mitigate CVE-2025-69627

Immediate Actions Required

• Upgrade Nitro PDF Pro for Windows to the latest patched version from the vendor
• Disable JavaScript execution in Nitro PDF Pro through application preferences until patching is complete
• Implement network filtering to block untrusted PDF documents from reaching vulnerable endpoints
• Deploy SentinelOne endpoint protection with memory exploitation detection enabled

Patch Information

Organizations should check Nitro for security updates addressing this vulnerability. The Jeroscope Security Advisory 2025 may contain additional remediation guidance. Users should upgrade from version 14.41.1.4 to the latest available patched release.

Workarounds

• Disable JavaScript execution in Nitro PDF Pro by navigating to Edit > Preferences > JavaScript and unchecking "Enable Acrobat JavaScript"
• Configure email gateway and web proxy rules to scan and quarantine PDF documents with embedded JavaScript
• Consider using alternative PDF readers for documents from untrusted sources until a patch is applied
• Implement application sandboxing to limit the impact of potential exploitation

# Registry configuration to disable JavaScript in Nitro PDF Pro (Windows)
# Run as Administrator
reg add "HKEY_CURRENT_USER\Software\Nitro\Pro\14.0\JavaScript" /v bEnableJS /t REG_DWORD /d 0 /f