CVE-2025-69627 Overview
CVE-2025-69627 is a heap use-after-free vulnerability [CWE-416] in Nitro PDF Pro for Windows version 14.41.1.4. The flaw resides in the JavaScript method this.mailDoc(). During execution, the application allocates an internal XID object and frees it prematurely. The freed pointer is then passed into UI and logging helper functions. Downstream routines such as wcscmp() may process invalid or stale pointers, producing access violations and non-deterministic crashes. Attacker-controlled JavaScript strings can influence the contents of the freed memory region, creating conditions that may enable code execution beyond simple denial of service.
Critical Impact
A specially crafted PDF document containing JavaScript can trigger memory corruption when opened in Nitro PDF Pro, potentially leading to arbitrary code execution in the context of the user.
Affected Products
- Gonitro Nitro PDF Pro 14.41.1.4
- Microsoft Windows (host platform)
- PDF documents processed by the vulnerable JavaScript engine
Discovery Timeline
- 2026-04-13 - CVE-2025-69627 published to NVD
- 2026-04-23 - Last updated in NVD database
Technical Details for CVE-2025-69627
Vulnerability Analysis
The vulnerability lives in the JavaScript runtime that Nitro PDF Pro exposes to embedded scripts inside PDF documents. The this.mailDoc() method instantiates an internal XID object on the heap to track the mail operation. The application releases this object before the surrounding workflow finishes referencing it. After the free, code paths that handle user-interface updates and diagnostic logging continue to operate on the dangling pointer. Functions such as wcscmp() dereference memory that may now contain reused heap chunks, partially overwritten structures, or remnants of attacker-controlled strings injected through earlier JavaScript calls.
Root Cause
The defect is an object lifecycle error in the mailDoc() implementation. The XID object is freed before the calling functions complete their use of the pointer. No nulling, reference counting, or ownership transfer protects the downstream consumers. Because the same heap region can be reclaimed by other JavaScript-controlled allocations, an attacker who shapes the heap can influence what data the freed pointer references when it is dereferenced.
Attack Vector
Exploitation requires a victim to open a malicious PDF file in Nitro PDF Pro. The CVSS vector indicates a local attack vector with no privileges or user interaction beyond document opening. The attacker crafts a PDF containing JavaScript that invokes this.mailDoc() with parameters designed to free the XID object and then re-enter the vulnerable code paths. By controlling heap layout through string allocations, the attacker can place chosen data into the freed region. When wcscmp() and the UI helpers read the dangling pointer, the result may be a controlled read, write, or indirect call, depending on heap state.
No public proof-of-concept code is available for this issue. Refer to the Jeroscope Security Advisory JERO-2025-016 for additional technical context.
Detection Methods for CVE-2025-69627
Indicators of Compromise
- PDF files containing JavaScript that invokes this.mailDoc() with anomalous string arguments or repeated calls intended to manipulate the heap.
- Application crash reports from NitroPDF.exe referencing access violations in wcscmp() or related UI and logging routines.
- Windows Error Reporting (WER) entries showing repeated faults in Nitro PDF Pro version 14.41.1.4 shortly after document open events.
Detection Strategies
- Inspect inbound PDF documents at email and web gateways for embedded JavaScript that calls mailDoc and contains long or repeated wide-character strings.
- Monitor endpoints for child processes, network connections, or shell activity spawned by NitroPDF.exe immediately after a document is opened.
- Correlate Nitro PDF Pro crash telemetry with recent file-open events to identify attempted exploitation that fails to achieve code execution.
Monitoring Recommendations
- Enable Windows Defender Exploit Guard or equivalent and forward exploit-related events to a central log store for review.
- Collect process creation, image load, and module crash telemetry from systems running Nitro PDF Pro.
- Track installed Nitro PDF Pro versions across the estate and alert on any host still running 14.41.1.4 after patches become available.
How to Mitigate CVE-2025-69627
Immediate Actions Required
- Inventory all Windows endpoints running Nitro PDF Pro and identify hosts on version 14.41.1.4.
- Restrict opening of PDF documents from untrusted sources, particularly external email attachments and unverified downloads.
- Disable JavaScript execution inside Nitro PDF Pro where business workflows allow it.
Patch Information
No vendor patch has been linked in the NVD entry at the time of publication. Monitor the Nitro vendor site and the Jeroscope Security Advisory JERO-2025-016 for the official fixed build. Apply the updated version across all endpoints as soon as it is released and validated.
Workarounds
- Disable JavaScript in Nitro PDF Pro preferences to block the vulnerable mailDoc() call path.
- Open untrusted PDFs in a sandboxed virtual machine or restricted user account with no access to sensitive data.
- Route inbound PDFs through a content-disarm-and-reconstruction (CDR) service that strips embedded JavaScript before delivery.
# Configuration example: disable JavaScript in Nitro PDF Pro via registry on Windows
reg add "HKCU\Software\Nitro\Pro\14.0\Settings" /v "EnableJavaScript" /t REG_DWORD /d 0 /f
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
