Multiple Vulnerabilities In Apache OpenOffice Result In Memory Corruption and Unauthorized Content Loading

Apache OpenOffice, a widely used open-source office suite, has long been a target for security researchers due to its robust feature set and legacy codebase.

The latest security bulletin from the Apache OpenOffice Security Team reveals multiple critical vulnerabilities fixed in version 4.1.16, primarily involving unauthorized remote content loading and memory corruption risks.

These flaws could enable attackers to deliver malware or exfiltrate sensitive data through specially crafted documents, underscoring the need for immediate updates among users in enterprise and individual settings.

The bulletin also recaps historical fixes, highlighting persistent challenges in document processing and third-party library dependencies.

As cybersecurity threats evolve, these disclosures underscore the importance of vigilant patch management for legacy software such as OpenOffice.

Recent Vulnerabilities Addressed In 4.1.16

The most pressing issues in Apache OpenOffice 4.1.16 revolve around missing authorization mechanisms that allow remote documents to load without prompting the user, creating avenues for phishing and malware distribution.

For instance, CVE-2025-64401 enables attackers to embed IFrames in documents that silently fetch external content, bypassing security warnings and potentially executing malicious scripts.

Similarly, CVE-2025-64402 exploits OLE objects to load remote files unobtrusively, a technique often used in targeted attacks against office users.

In Calc spreadsheets, CVE-2025-64403 targets external data sources, while CVE-2025-64404 abuses background and bullet images to pull in unauthorized content without detection.

Beyond content loading, CVE-2025-64405 leverages the DDE function in Calc to automate remote fetches, amplifying risks in automated workflows.

A more severe concern is CVE-2025-64406, an out-of-bounds write vulnerability during CSV imports that could lead to memory corruption, program crashes, or arbitrary code execution if exploited with crafted files.

This “Important”- rated flaw poses a direct threat to system integrity, as attackers could exploit it via social engineering to compromise endpoints.

Finally, CVE-2025-64407 allows URL schemes in documents to exfiltrate INI file values and environment variables, enabling reconnaissance of system configurations without user awareness.

All these affect versions up to 4.1.15, with proof-of-concept exploits available for several of them. However, no widespread attacks have been reported yet.

Historical Context and Mitigation Strategies

Apache OpenOffice’s security history is marked by recurring memory corruption and code-execution flaws, often stemming from file-format parsers and embedded objects.

Earlier releases, like 4.1.15, patched use-after-free issues in the expat libraries (CVE-2022-43680, CVE-2022-40674) and arbitrary file writes in Base (CVE-2023-1183).

At the same time, 4.1.14 addressed macro execution without warnings (CVE-2022-47502).

Going further back, versions from 4.1.11 to 3.4.0 fixed buffer overflows, privilege escalations, and third-party library vulnerabilities such as those in Expat and libxml2.

Even older releases, such as the OpenOffice.org 3.2 and 2.4 series, addressed heap overflows in WMF/EMF processing and in the manipulation of ODF files.

To mitigate these risks, organizations should prioritize upgrading to Apache OpenOffice 4.1.16, available via the official download page, which includes cumulative fixes.

Disable macros and external links by default in security settings, and employ endpoint detection tools to monitor document openings.

For legacy users, consider migrating to actively maintained alternatives like LibreOffice, which shares similar vulnerabilities but receives more frequent updates.

Subscribing to the security-alerts mailing list ensures timely notifications. Regular vulnerability scanning and user training on phishing tactics remain essential in defending against these document-based threats.