CVE-2026-21496: iccDEV NULL Pointer DoS Vulnerability

CVE-2026-21496 Overview

CVE-2026-21496 is a Null Pointer Dereference vulnerability affecting iccDEV, a collection of libraries and tools designed for the interaction, manipulation, and application of ICC color management profiles. Prior to version 2.3.1.2, iccDEV is vulnerable to a NULL pointer dereference via the signature parser, which can lead to application crashes and denial of service conditions.

Critical Impact
An attacker can craft malicious ICC profile data that triggers a NULL pointer dereference in the signature parser, causing applications using iccDEV to crash unexpectedly. This can result in denial of service for systems processing untrusted color profiles.

Affected Products

iccDEV versions prior to 2.3.1.2
Applications and systems utilizing the iccDEV library for ICC color profile processing
International Color Consortium tools built on the vulnerable iccDEV codebase

Discovery Timeline

2026-01-07 - CVE CVE-2026-21496 published to NVD
2026-01-08 - Last updated in NVD database

Technical Details for CVE-2026-21496

Vulnerability Analysis

This vulnerability exists in the icGetSigVal() function located in IccProfLib/IccUtil.cpp. The function processes signature values from ICC color profiles without validating that the input buffer pointer is non-NULL before attempting to access it. When a NULL pointer is passed to this function, calling strlen(pBuf) triggers a NULL pointer dereference, resulting in a segmentation fault and application crash.

The local attack vector requires user interaction—specifically, the victim must open or process a maliciously crafted ICC profile file. This vulnerability primarily impacts availability, as successful exploitation results in a denial of service condition. There is no direct impact on confidentiality or integrity of the system.

Root Cause

The root cause is categorized as CWE-20 (Improper Input Validation). The icGetSigVal() function in IccProfLib/IccUtil.cpp failed to perform NULL pointer validation on the pBuf parameter before attempting to determine its length using strlen(). This missing input validation check allowed NULL pointers to propagate into the function, leading to undefined behavior and application crashes when the pointer was dereferenced.

Attack Vector

The attack vector is local, requiring an attacker to provide a specially crafted ICC color profile file to a vulnerable application. The exploitation scenario typically involves:

An attacker creates a malformed ICC profile containing data that causes the signature parser to pass a NULL value to icGetSigVal()
The victim opens or processes the malicious ICC profile using an application linked against a vulnerable version of iccDEV
When the signature parser attempts to process the malformed data, it passes a NULL pointer to icGetSigVal()
The function dereferences the NULL pointer when calling strlen(pBuf), causing a segmentation fault
The application crashes, resulting in denial of service

cpp

// Security patch in IccProfLib/IccUtil.cpp
// Source: https://github.com/InternationalColorConsortium/iccDEV/commit/0e51ceb427925b7e22f0465547df7506d35cda1c

 icUInt32Number icGetSigVal(const icChar *pBuf)
 {
   icUInt32Number v;
+  
+  if (!pBuf)    // can't return an error, so do something sane to avoid a segfault
+    return 0;
 
   switch(strlen(pBuf)) {
     case 0:

Detection Methods for CVE-2026-21496

Indicators of Compromise

Unexpected application crashes when processing ICC color profile files
Segmentation fault errors in application logs referencing icGetSigVal or IccUtil.cpp
Abnormal termination of image processing or color management services
Core dump files generated during ICC profile parsing operations

Detection Strategies

Monitor application crash reports for signatures related to NULL pointer dereference in ICC profile processing libraries
Implement file integrity monitoring on iccDEV library files to detect unauthorized or unpatched versions
Deploy static code analysis tools to identify vulnerable iccDEV versions in your software supply chain
Use dependency scanning to identify applications linking against iccDEV versions prior to 2.3.1.2

Monitoring Recommendations

Enable crash reporting and log aggregation for applications that process ICC color profiles
Monitor for unusual patterns of application crashes that correlate with ICC profile file operations
Implement anomaly detection for repeated crash events targeting color management functionality
Track file access patterns for ICC profile files from untrusted sources

How to Mitigate CVE-2026-21496

Immediate Actions Required

Upgrade iccDEV to version 2.3.1.2 or later immediately
Audit all applications and services that utilize iccDEV for ICC profile processing
Restrict processing of ICC profiles from untrusted sources until patching is complete
Implement input validation at the application layer for ICC profile files

Patch Information

The vulnerability has been patched in iccDEV version 2.3.1.2. The fix adds a NULL pointer check at the beginning of the icGetSigVal() function, returning a default value of 0 when a NULL pointer is detected instead of attempting to dereference it. For detailed information about the patch, refer to the GitHub Security Advisory GHSA-wj8m-6w77-r4rw and the associated Pull Request #405.

Workarounds

Implement application-level validation to reject ICC profiles from untrusted or unverified sources
Deploy sandboxing or process isolation for applications that must process untrusted ICC profiles
Configure applications to fail gracefully when encountering malformed ICC profile data
Use network segmentation to limit exposure of systems processing ICC color profiles

bash

# Configuration example - Verify iccDEV version
# Check installed iccDEV version and update if necessary
git clone https://github.com/InternationalColorConsortium/iccDEV.git
cd iccDEV
git checkout tags/v2.3.1.2
# Rebuild and reinstall the library
mkdir build && cd build
cmake ..
make && sudo make install