CVE-2026-21505: iccDEV Undefined Behavior Vulnerability

CVE-2026-21505 Overview

CVE-2026-21505 is an Input Validation Error vulnerability affecting iccDEV, a set of libraries and tools developed by the International Color Consortium (ICC) for the interaction, manipulation, and application of ICC color management profiles. Prior to version 2.3.1.2, iccDEV exhibits undefined behavior due to an invalid enum value, which can be exploited to cause application crashes and denial of service conditions.

Critical Impact
This vulnerability can lead to undefined behavior and application crashes when processing malformed ICC profile data, potentially causing denial of service in applications that rely on iccDEV for color management operations.

Affected Products

iccDEV versions prior to 2.3.1.2
Applications utilizing iccDEV libraries for ICC profile processing
Systems processing untrusted ICC color management profiles

Discovery Timeline

2026-01-07 - CVE CVE-2026-21505 published to NVD
2026-01-08 - Last updated in NVD database

Technical Details for CVE-2026-21505

Vulnerability Analysis

The vulnerability resides in the icProfileHeader.h header file within the IccProfLib component. The root issue stems from the icMaterialColorSignature enum type definition, which lacked proper bounds and type specification. When the library processes ICC profile data containing values outside the expected enum range, the C/C++ standard does not define the resulting behavior, leading to undefined behavior conditions.

This undefined behavior is particularly dangerous because it can manifest differently across compilers, optimization levels, and platforms. In practical terms, an attacker can craft a malicious ICC profile that triggers this condition when processed by applications using vulnerable versions of iccDEV.

Root Cause

The vulnerability is classified under CWE-20 (Improper Input Validation). The icMaterialColorSignature enum was defined without explicit underlying type specification and lacked sentinel values to help sanitization tools detect out-of-range values. When ICC profile data contained material color signature values not explicitly enumerated, the compiler's assumptions about valid enum ranges could be violated, resulting in undefined behavior.

Attack Vector

The attack requires local access with user interaction, as an attacker must convince a user to open or process a maliciously crafted ICC profile file. The attack flow involves:

Attacker creates a malformed ICC profile with an invalid material color signature value
Victim application uses iccDEV library to process the malicious profile
The invalid enum value triggers undefined behavior
Application crashes or exhibits unpredictable behavior, resulting in denial of service

The following patch demonstrates the fix implemented in version 2.3.1.2:

 } icColorSpaceSignature;
 
 
-typedef enum {
+typedef enum : icUInt32Number {
   icSigNoMCSData                 = 0x00000000,
   icSigMCSData                   = 0x6d630000,  /* "mc0000" */
-  /*Note: "nc0001" through "ncFFFF" are also valid signatures defined using macro icNColorSpaceSig()*/
+  /*Note: "mc0001" through "mcFFFF" are also valid signatures defined using macro icNColorSpaceSig()*/
+  icSigMCSDataEnd                = 0x6d63FFFF,   // provide clues to UBSan
+
+  icSigMCSMaxEnumData            = 0xFFFFFFFF,
 } icMaterialColorSignature;
 
 #define icGetColorSpaceType(sig) ((icColorSpaceSignature)(((icUInt32Number)sig)&0xffff0000))

Source: GitHub Commit

Detection Methods for CVE-2026-21505

Indicators of Compromise

Unexpected application crashes when processing ICC profile files
UndefinedBehaviorSanitizer (UBSan) reports indicating invalid enum values in iccDEV library functions
Core dumps or crash logs referencing icMaterialColorSignature or related color profile processing functions

Detection Strategies

Enable UndefinedBehaviorSanitizer during development and testing to detect invalid enum value usage
Implement file integrity monitoring for ICC profile directories to detect potentially malicious files
Deploy application crash monitoring to identify patterns of denial of service attempts
Audit applications for iccDEV library usage and verify version numbers against vulnerable releases

Monitoring Recommendations

Monitor application logs for abnormal terminations during color profile processing operations
Implement input validation at the application layer before passing ICC profiles to iccDEV
Track iccDEV library versions across the environment using software composition analysis tools
Configure endpoint detection to alert on repeated application crashes related to color management

How to Mitigate CVE-2026-21505

Immediate Actions Required

Upgrade iccDEV to version 2.3.1.2 or later immediately
Audit all applications in your environment that depend on iccDEV libraries
Restrict processing of ICC profiles from untrusted sources until patching is complete
Enable compiler sanitizers in development environments to catch similar issues

Patch Information

The vulnerability has been patched in iccDEV version 2.3.1.2. The fix explicitly specifies icUInt32Number as the underlying type for the icMaterialColorSignature enum and adds sentinel values (icSigMCSDataEnd and icSigMCSMaxEnumData) to provide proper bounds for sanitization tools.

For detailed patch information, refer to:

Workarounds

Implement input validation to reject ICC profiles from untrusted sources before processing
Deploy application sandboxing to limit the impact of crashes caused by malformed profiles
Compile applications with UndefinedBehaviorSanitizer to trap invalid enum values during testing
Consider implementing file type verification for ICC profiles before passing to processing functions

bash

# Verify iccDEV version in your environment
# Check for vulnerable versions and update package managers accordingly
pkg-config --modversion iccDEV

# Compile with UBSan for testing environments
export CXXFLAGS="-fsanitize=undefined -fno-sanitize-recover=all"