CVE-2026-21494: iccDEV Buffer Overflow Vulnerability

CVE-2026-21494 Overview

CVE-2026-21494 is a heap buffer overflow vulnerability affecting the iccDEV library, a set of libraries and tools that enable interaction, manipulation, and application of International Color Consortium (ICC) color management profiles. The vulnerability exists in the CIccTagLut8::Validate() function and affects users who process ICC color profiles using versions prior to 2.3.1.2.

Critical Impact

Processing a maliciously crafted ICC color profile can trigger a heap buffer overflow, potentially leading to denial of service or information disclosure on affected systems.

Affected Products

• iccDEV library versions prior to 2.3.1.2
• Applications utilizing the iccDEV library for ICC profile processing
• Systems processing untrusted ICC color profile data

Discovery Timeline

• 2026-01-06 - CVE CVE-2026-21494 published to NVD
• 2026-01-08 - Last updated in NVD database

Technical Details for CVE-2026-21494

Vulnerability Analysis

This vulnerability is classified as CWE-122 (Heap-based Buffer Overflow). The flaw resides in the validation logic of the CIccTagLut8 class within the iccDEV library. When processing ICC color profiles, the library performs validation of Look-Up Table (LUT) tags, but insufficient bounds checking in the CIccTagLut8::Validate() function allows malformed input to trigger a heap buffer overflow condition.

The vulnerability requires local access and user interaction, meaning an attacker must convince a victim to process a specially crafted ICC profile file. Upon successful exploitation, an attacker could cause application crashes resulting in denial of service, or potentially leak sensitive memory contents. The attack complexity is low, and no special privileges are required to exploit this vulnerability.

Root Cause

The root cause stems from improper validation of input/output channel counts in the LUT validation routines. The original code attempted to derive expected channel counts from profile header fields (pProfile->m_Header.colorSpace and pProfile->m_Header.pcs) and then iterate over curves based on these derived values. However, when processing a malformed profile, mismatches between expected and actual channel counts could cause the validation code to access memory beyond allocated buffer boundaries.

The fix modifies the validation logic to use the actual channel counts (m_nInput and m_nOutput) as read from the LUT data itself, rather than deriving them from header fields. This ensures the validation code operates within the bounds of actually allocated memory, even when processing malformed profiles.

Attack Vector

The attack vector requires local access to the target system. An attacker would need to craft a malicious ICC color profile with manipulated LUT tag data and convince a victim to process this file using an application that relies on the vulnerable iccDEV library. This could occur through:

• Tricking users into opening malicious image files with embedded ICC profiles
• Compromising color management workflows in design or publishing applications
• Exploiting automated ICC profile processing pipelines

The following patch demonstrates the security fix applied to address the heap buffer overflow in IccTagLut.cpp:

   case icSigBToA2Tag:
   case icSigGamutTag:
     {
-      icUInt32Number nInput = icGetSpaceSamples(pProfile->m_Header.pcs);
+//      icUInt32Number nInput = icGetSpaceSamples(pProfile->m_Header.colorSpace);
+//      icUInt32Number nOutput = icGetSpaceSamples(pProfile->m_Header.pcs);
+// m_nInput should match nInput, and m_nOutput should match nOutput
+// That is validated in CIccMBB::Validate
+// Here we don't want to crash while validating the curves, even if the count of them is incorrect, so we use the same counts obtained from reading the LUT.

+      icUInt32Number nInput = m_nInput;
+      icUInt32Number nOutput = m_nOutput;

-      icUInt32Number nOutput;
       if (sig==icSigGamutTag) {
         nOutput = 1;
       }
-      else {
-        nOutput = icGetSpaceSamples(pProfile->m_Header.colorSpace);
-      }
-
-      if (m_nOutput!=nOutput) {
-        sReport += icMsgValidateCriticalError;
-        sReport += sSigPathName;
-        sReport += " - Incorrect number of output channels.\n";
-        rv = icMaxStatus(rv, icValidateCriticalError);
-      }

       icUInt8Number i;
       if (m_CurvesB) {

Source: GitHub Commit

Detection Methods for CVE-2026-21494

Indicators of Compromise

• Application crashes or abnormal termination when processing ICC color profile files
• Memory access violations or segmentation faults in processes using iccDEV library functions
• Unexpected behavior in color management operations within affected applications
• Core dumps or crash logs referencing CIccTagLut8::Validate() or related validation functions

Detection Strategies

• Monitor for crashes in applications that process ICC profiles and utilize the iccDEV library
• Implement file integrity monitoring on systems that handle ICC color profiles from untrusted sources
• Deploy endpoint detection and response (EDR) solutions capable of detecting heap corruption attempts
• Review application logs for errors related to ICC profile validation failures

Monitoring Recommendations

• Enable crash reporting and analysis for applications using iccDEV library functionality
• Monitor system logs for memory corruption indicators in color management processes
• Track file access patterns for ICC profile files, particularly from external or untrusted sources
• Configure SentinelOne to detect memory corruption exploitation attempts in protected applications

How to Mitigate CVE-2026-21494

Immediate Actions Required

• Upgrade iccDEV library to version 2.3.1.2 or later immediately
• Identify all applications and systems using the vulnerable iccDEV library versions
• Restrict processing of ICC profiles from untrusted sources until patching is complete
• Review and audit color management workflows for exposure to malicious profile inputs

Patch Information

The vulnerability has been addressed in iccDEV version 2.3.1.2. The patch modifies the CIccTagLut8::Validate() function to use actual channel counts from the parsed LUT data rather than deriving them from potentially mismatched header fields. For technical details, refer to the GitHub Security Advisory and the associated commits (Commit 7c2cb71, Commit e91fe72).

Workarounds

• No known workarounds are available according to the vendor advisory
• Apply defense-in-depth by isolating color profile processing to sandboxed environments
• Validate ICC profiles using external tools before processing in production environments
• Limit exposure by restricting which users and processes can handle external ICC profile files

# Verify iccDEV library version after update
# Check installed library version
pkg-config --modversion iccDEV 2>/dev/null || echo "Check version via application-specific methods"

# Rebuild dependent applications after library upgrade
./configure && make clean && make && make install