CVE-2025-9900 – This CVE describes a write-what-where vulnerabi... (How to Fix)

Q: What is the severity of CVE-2025-9900?

CVE-2025-9900 has a CVSS score of 8.8 (HIGH). This CVE describes a write-what-where vulnerability in Libtiff where processing a specially crafted TIFF image with an abnormally large height value allows an attacker to write arbitrary color data to any memory location. This can lead to denial of service (application crashes) or arbitrary code execution with user permissions. Any system or application using vulnerable versions of Libtiff to process TIFF images is affected.

📋 TL;DR

This CVE describes a write-what-where vulnerability in Libtiff where processing a specially crafted TIFF image with an abnormally large height value allows an attacker to write arbitrary color data to any memory location. This can lead to denial of service (application crashes) or arbitrary code execution with user permissions. Any system or application using vulnerable versions of Libtiff to process TIFF images is affected.

💻 Affected Systems

Products:

Libtiff

Versions: Specific versions not provided in CVE description; check Red Hat advisories for details.

Operating Systems: Linux, Windows, macOS, Unix-like systems

Default Config Vulnerable: ⚠️ Yes

Notes: Any application or service that uses Libtiff to process TIFF images is vulnerable, including web servers, image processing tools, and document viewers.

⚠️ Manual Verification Required

This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.

Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).

🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.

Recommended Actions:

Review the CVE details at NVD
Check vendor security advisories for your specific version
Test if the vulnerability is exploitable in your environment
Consider updating to the latest version as a precaution

⚠️ Risk & Real-World Impact

🔴

Worst Case

Arbitrary code execution with the permissions of the user running the vulnerable application, potentially leading to full system compromise.

🟠

Likely Case

Application crash (denial of service) when processing malicious TIFF files, disrupting services that handle image processing.

🟢

If Mitigated

Limited impact if proper input validation and memory protections are in place, potentially causing only crashes without code execution.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires crafting a malicious TIFF file and tricking a user or system into processing it; no authentication is needed.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check Red Hat advisories for specific patched versions (e.g., via RHSA-2025:17651).

Vendor Advisory: https://access.redhat.com/errata/RHSA-2025:17651

Restart Required: Yes

Instructions:

1. Identify affected systems using Libtiff. 2. Apply the latest patches from your vendor (e.g., Red Hat, Ubuntu). 3. Restart services or applications that use Libtiff to ensure the patch is active.

🔧 Temporary Workarounds

Disable TIFF Processing

all

Block or disable processing of TIFF files in vulnerable applications to prevent exploitation.

# Example for a web server: configure to reject TIFF MIME types
# Use application-specific settings to disable TIFF support

Input Validation

linux

Implement strict input validation to reject TIFF files with abnormal metadata values like large heights.

# Custom script to check TIFF metadata before processing
# Use tools like 'tiffinfo' to validate files

🧯 If You Can't Patch

Implement network segmentation to isolate systems using Libtiff from untrusted sources.
Use application whitelisting to restrict execution of vulnerable applications.

🔍 How to Verify

Check if Vulnerable:

Check the Libtiff version on your system; if it's within the affected range (consult Red Hat advisories), it is vulnerable.

Check Version:

tiffinfo --version  # On Linux/Unix systems

Verify Fix Applied:

Verify that the Libtiff version has been updated to a patched version as specified in vendor advisories.

📡 Detection & Monitoring

Log Indicators:

Application crashes or errors when processing TIFF files
Unusual memory access patterns in system logs

Network Indicators:

Inbound transfers of TIFF files to vulnerable systems
Outbound connections after processing suspicious TIFF files

SIEM Query:

Example: search for 'libtiff' AND 'crash' OR 'error' in application logs within the last 24 hours.

📊 Metadata

CVE ID: CVE-2025-9900

CVSS v3 Score: 8.8 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-123

EPSS Score: 0.06% exploit probability (17th percentile)

Published: September 23, 2025

Last Updated: February 27, 2026

🔗 References

📤 Share & Export

📄 Export Markdown 📋 Export JSON

🔗 Related Vulnerabilities

If you're affected by CVE-2025-9900, you might also want to check these: