Summary
CVE-2025-27831 is a serious buffer overflow bug in Ghostscript versions before 10.05.0. It happens because the DOCXWRITE and TXTWRITE devices don’t properly check long UTF-8 text lengths. Malicious files can cause crashes or allow remote code execution, especially on systems that automatically handle untrusted documents. No public exploit is known yet, but the risk is high. The issue is fixed in Ghostscript 10.05.0, and major Linux distros have released patches. Immediate updating is recommended.
Urgent Actions Required
- Update Ghostscript to version 10.05.0 or later immediately.
- Avoid processing untrusted files with DOCXWRITE or TXTWRITE devices.
- Run Ghostscript in a sandboxed or restricted environment if patching is delayed.
- Restrict Ghostscript usage to trusted inputs only.
- Monitor for crashes or abnormal activity in Ghostscript-based services.
Which Systems Are Vulnerable to CVE-2025-27831?
Technical Overview
- Vulnerability Type: Classic Buffer Overflow (CWE-120) via improper bounds checking in text buffer
- Affected Software/Versions:
- Artifex Ghostscript prior to 10.05.0
- Notably affects output devices: DOCXWRITE and TXTWRITE
- Attack Vector: Network (via crafted input files like PDF, DOCX, or TXT)
- CVSS Score: 9.8
- Exploitability Score:
- Attack Vector: Network
- Attack Complexity: Low
- Privileges Required: None
- User Interaction: None
- Scope: Unchanged
- Confidentiality Impact: High
- Integrity Impact: High
- Availability Impact: High
- Patch Availability: Yes — fixed in Ghostscript 10.05.03
How Does the CVE-2025-27831 Exploit Work?
The attack typically follows these steps:
What Causes CVE-2025-27831?
Vulnerability Root Cause:
This vulnerability is caused by missing bounds checks in Ghostscript’s DOCXWRITE and TXTWRITE devices. When handling long or malformed UTF-8 text, Ghostscript writes to a fixed-size buffer without checking its limits, leading to a buffer overflow. This can crash the system or allow code execution, especially when processing untrusted files automatically.
How Can You Mitigate CVE-2025-27831?
If immediate patching is delayed or not possible:
- Turn off DOCXWRITE and TXTWRITE if you don’t need them.
- Run Ghostscript in a sandbox (like Docker or AppArmor) to reduce risk.
- Only process files from trusted sources.
- Check files for unusually long or broken text before using them.
- Watch Ghostscript for crashes or strange behavior with uploaded files.
- Run Ghostscript with limited permissions to reduce damage if attacked.
Which Assets and Systems Are at Risk?
Asset Types Affected:
- Document Conversion Services – Apps or tools that use Ghostscript’s DOCXWRITE or TXTWRITE devices to convert or process documents.
- Print Servers – Systems handling PostScript or PDF print jobs with Ghostscript.
- Cloud-based File Handlers – Platforms that allow users to upload documents for preview or conversion using Ghostscript.
Business-Critical Systems at Risk:
- Automated Document Pipelines – Systems that auto-process user files (e.g., PDFs, DOCX) are at high risk of remote exploitation.
- Content Management Systems (CMS) – If Ghostscript is used to render uploaded documents.
- SaaS Platforms with Document Preview Features – Risk of user-to-system compromise via crafted uploads.
- Secure Printing Infrastructure – If Ghostscript runs with elevated privileges.
Exposure Level:
- Internet-facing File Conversion APIs – Especially those accepting untrusted files without sandboxing.
- Intranet tools that batch-process documents – If not patched, remain vulnerable despite being internal.
- CI/CD or staging environments using Ghostscript for tests – May be overlooked but still vulnerable to crafted file uploads.
Will Patching CVE-2025-27831 Cause Downtime?
Patch application impact: Low to moderate. Updating to Ghostscript 10.05.0 or later resolves the vulnerability. Most systems just need to replace the Ghostscript package and restart dependent services. Debian, Ubuntu, and other Linux distros provide Ghostscript security updates via package managers. Test updates in staging before deploying, especially if using custom devices or scripts.
Mitigation (if immediate patching is not possible):
Partial mitigation is possible by:
- Running Ghostscript in a sandboxed or containerized environment (e.g., Docker, AppArmor, chroot).
- Limiting privileges (e.g., running as nobody or lp user).
- Restricting input by avoiding processing of untrusted documents.
- Monitoring for abnormal crashes or memory issues in Ghostscript services.
However, these are not full mitigations. Systems remain exposed until version 10.05.0 or later is applied.
How Can You Detect CVE-2025-27831 Exploitation?
Remediation & Response
Patch/Upgrade Instructions:
- Upgrade to Ghostscript version 10.05.0 or later to fix the vulnerability.
Official download: https://ghostscript.com/download/gsdnld.html
Mitigation Steps if No Patch:
- Restrict Ghostscript from processing untrusted input, especially through DOCXWRITE or TXTWRITE devices.
- Run Ghostscript in a sandboxed or isolated environment, such as using Docker, AppArmor, or chroot.
- Limit privileges by executing Ghostscript as a low-privileged user (e.g., lp, nobody) to reduce the impact of exploitation.
- Monitor logs for crashes, memory faults, or abnormal behavior in Ghostscript-based services.
Remediation Timeline:
- Immediately (0–2 hrs): Block processing of untrusted documents in automated services.
- Within 8 hrs: Apply the Ghostscript update on all critical document processing systems.
- Within 24 hrs: Verify that no affected versions (<10.05.0) are running in production or ci/cd pipelines.
Incident Response Considerations:
- Investigate any Ghostscript crashes or segmentation faults to determine possible exploitation.
- Review system logs for memory corruption or buffer overflow indicators tied to doc_common.c.
- If compromise is suspected, audit for unauthorized file writes or process execution linked to Ghostscript.
Where Can I Find More Information on CVE-2025-27831?
CVSS Breakdown Table
| Metric | Value | Description |
|---|---|---|
| Base Score | 9.8 | Critical severity; allows full system compromise with low effort |
| Attack Vector | Network | Exploitable remotely, especially in automated document-processing pipelines |
| Attack Complexity | Low | Exploitation is straightforward; no special conditions needed |
| Privileges Required | None | No authentication or user privileges required to exploit |
| User Interaction | None | Exploitation does not require any user input or action |
| Scope | Unchanged | Impact remains within the vulnerable component (Ghostscript) |
| Confidentiality Impact | High | Exploit may lead to unauthorized access to sensitive memory or files |
| Integrity Impact | High | Allows potential modification of memory, file contents, or execution flow |
| Availability Impact | High | Can crash services or cause denial-of-service via memory corruption |
