CVE-2026-21501: iccDEV Buffer Overflow Vulnerability

CVE-2026-21501 Overview

A stack overflow vulnerability has been identified in iccDEV, a library suite that provides tools for interaction, manipulation, and application of ICC color management profiles. The vulnerability exists in the calculator parser component prior to version 2.3.1.2, where improper input validation can lead to a stack overflow condition when processing maliciously crafted ICC profile data.

Critical Impact

Exploitation of this vulnerability can cause a denial of service condition, crashing applications that utilize the iccDEV library when processing specially crafted ICC color profiles.

Affected Products

• iccDEV versions prior to 2.3.1.2
• Applications and systems utilizing the iccDEV library for ICC color profile processing
• IccProfLib component (specifically IccMpeCalc.cpp)

Discovery Timeline

• 2026-01-07 - CVE CVE-2026-21501 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2026-21501

Vulnerability Analysis

This vulnerability affects the calculator parser in iccDEV's IccProfLib component. The flaw exists in the CIccMpeCalculator::Read() function within IccMpeCalc.cpp, where insufficient bounds checking allows for recursive calls that can exhaust the stack. When processing ICC profiles containing malformed calculator elements, the parser fails to properly validate sub-element offsets, leading to uncontrolled recursion and ultimately a stack overflow condition.

The vulnerability requires local access and user interaction, meaning an attacker must convince a user to open a maliciously crafted ICC profile file. While this limits the attack surface, the impact is significant for applications that process untrusted ICC profiles, potentially leading to complete application crashes and denial of service.

Root Cause

The root cause is improper input validation (CWE-20) in the calculator element parsing logic. Specifically, the header size calculation was incorrect, using individual icUInt16Number fields instead of the proper icUInt32Number for SubElement count and icPositionNumber structure. This miscalculation allowed malformed profiles to bypass size validation checks, enabling recursive parsing that exhausts the call stack.

Attack Vector

The attack requires local access where a threat actor crafts a malicious ICC profile with specially constructed calculator elements containing recursive references. When a victim opens or processes this profile using an application built with the vulnerable iccDEV library, the parser enters an infinite recursion loop, consuming stack memory until the process crashes.

The attack chain involves:

1. Crafting an ICC profile with malformed calculator sub-elements
2. Distributing the malicious profile to targets (via email, download, etc.)
3. User opens the profile with a vulnerable application
4. Stack overflow triggers, causing denial of service

// Security patch showing the header size calculation fix
// Source: https://github.com/InternationalColorConsortium/iccDEV/commit/798be59011649a26a529600cc3cd56437634d3d0

 
   size_t startPos = pIO->Tell();
   
-  size_t headerSize = sizeof(icTagTypeSignature) + 
-    sizeof(icUInt32Number) + 
-    sizeof(icUInt16Number) + 
-    sizeof(icUInt16Number) +
-    sizeof(icUInt16Number) +
-    sizeof(icUInt16Number) +
-    sizeof(icUInt16Number) +
-    sizeof(icUInt16Number);
+  size_t headerSize = sizeof(icTagTypeSignature) + // typeSig
+    sizeof(icUInt32Number) +    // reserved
+    sizeof(icUInt16Number) +    // inputChannels
+    sizeof(icUInt16Number) +    // outputChannels
+    sizeof(icUInt32Number) +    // SubElement count
+    sizeof(icPositionNumber);   // at least one icPositionNumber
 
   if (headerSize > size)
     return false;

Detection Methods for CVE-2026-21501

Indicators of Compromise

• Application crashes when processing ICC profile files
• Stack exhaustion errors in system logs related to iccDEV or color profile processing
• Unexpected high memory usage followed by process termination when handling ICC files
• Core dumps or crash reports showing CIccMpeCalculator::Read() in the call stack

Detection Strategies

• Monitor for process crashes in applications known to use iccDEV library
• Implement file integrity monitoring for ICC profile directories to detect suspicious profile uploads
• Deploy application-level logging to track ICC profile parsing operations and failures
• Use behavioral analysis to identify unusual patterns in color management operations

Monitoring Recommendations

• Enable verbose logging for applications that process ICC color profiles
• Monitor system event logs for stack overflow exceptions in relevant processes
• Track file access patterns to ICC profile directories for anomalous activity
• Configure alerts for repeated application crashes involving color management functions

How to Mitigate CVE-2026-21501

Immediate Actions Required

• Upgrade iccDEV to version 2.3.1.2 or later immediately
• Audit applications and systems to identify all instances of iccDEV library usage
• Restrict processing of ICC profiles from untrusted sources until patched
• Implement input validation for ICC profile files before processing

Patch Information

The vulnerability has been addressed in iccDEV version 2.3.1.2. The fix corrects the header size calculation in CIccMpeCalculator::Read() to properly account for the SubElement count and position number structures. Additionally, the patch adds validation checks for sub-element offsets to prevent recursive parsing. For detailed information, refer to the GitHub Security Advisory, the related GitHub Issue #365, and the Pull Request #413.

Workarounds

• Disable processing of untrusted ICC profiles until the patch is applied
• Implement application-level sandboxing to limit the impact of crashes
• Deploy stack size limits and monitoring for applications processing ICC profiles
• Use file type validation to reject malformed ICC profiles before parsing

# Configuration example - Update iccDEV library
git clone https://github.com/InternationalColorConsortium/iccDEV.git
cd iccDEV
git checkout v2.3.1.2
mkdir build && cd build
cmake ..
make && sudo make install