CVE-2026-21490: iccDEV Library Buffer Overflow Flaw

CVE-2026-21490 Overview

CVE-2026-21490 is a heap buffer overflow vulnerability affecting the iccDEV library, a collection of libraries and tools used for interacting with, manipulating, and applying International Color Consortium (ICC) color management profiles. The vulnerability exists in the CIccTagLut16::Validate() function and can be triggered when processing maliciously crafted ICC color profiles.

Critical Impact
A heap buffer overflow in CIccTagLut16::Validate() can lead to denial of service through application crashes, with potential for limited information disclosure when processing untrusted ICC color profiles.

Affected Products

iccDEV library versions prior to 2.3.1.2
Applications and services that utilize iccDEV for ICC color profile processing
Color management systems integrating vulnerable iccDEV library versions

Discovery Timeline

January 6, 2026 - CVE-2026-21490 published to NVD
January 8, 2026 - Last updated in NVD database

Technical Details for CVE-2026-21490

Vulnerability Analysis

This heap buffer overflow vulnerability (CWE-122) affects users of the iccDEV library who process ICC color profiles. The flaw resides in the CIccTagLut16::Validate() function within the IccTagLut.cpp file. When validating Look-Up Table (LUT) tags within ICC profiles, the code previously used channel counts derived from the profile header rather than the actual values read from the LUT structure itself.

This mismatch between expected and actual channel counts creates conditions where the validation routines can access memory beyond allocated buffer boundaries. An attacker can craft a malicious ICC profile with mismatched channel configuration to trigger the overflow condition, potentially causing application crashes or memory corruption.

The vulnerability requires local access and user interaction—specifically, a user must open or process a maliciously crafted ICC profile file. While the primary impact is denial of service through application crashes, there is also potential for limited information disclosure through out-of-bounds read operations.

Root Cause

The root cause stems from improper validation of input channel counts in the LUT validation logic. The original implementation calculated expected input and output channel counts using icGetSpaceSamples() based on profile header color space values. However, the actual LUT data structures may contain different channel counts than specified in the header.

When iterating over curves during validation, the code would use header-derived counts to iterate over curve arrays, but these arrays were allocated based on the counts actually read from the LUT structure. This size mismatch results in heap buffer overflows when the header-specified count exceeds the actual allocated size.

Attack Vector

Exploitation requires local access with user interaction. An attacker must craft a malicious ICC color profile with inconsistent channel specifications between the profile header and the embedded LUT structures. The attack vector involves:

Creating an ICC profile where the header declares one color space configuration
Embedding LUT structures with different channel counts than the header specifies
Distributing the malicious profile to target systems
Triggering profile validation through normal application workflows

When a vulnerable application processes such a profile, the CIccTagLut16::Validate() function iterates beyond the bounds of allocated curve arrays, causing heap corruption.

The following patch demonstrates how the vulnerability was addressed in the IccTagLut.cpp file:

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 e91fe722

Detection Methods for CVE-2026-21490

Indicators of Compromise

Unexpected application crashes when opening or processing ICC color profile files
Memory access violation errors in applications utilizing the iccDEV library
Crash dumps indicating faults in CIccTagLut16::Validate() or related LUT validation functions
Anomalous ICC profile files with inconsistent header and LUT channel configurations

Detection Strategies

Monitor application crash reports for patterns involving ICC profile processing or iccDEV library functions
Implement file integrity monitoring for ICC profile files in production environments
Deploy memory corruption detection tools (AddressSanitizer, Valgrind) during development and testing of applications using iccDEV
Scan for iccDEV library versions older than 2.3.1.2 across software inventory

Monitoring Recommendations

Enable detailed logging for ICC profile parsing operations in applications using iccDEV
Set up crash monitoring and alerting for production systems that process ICC color profiles
Implement file upload validation to detect malformed ICC profiles before processing
Monitor for unusual patterns of ICC profile file access or processing attempts

How to Mitigate CVE-2026-21490

Immediate Actions Required

Update the iccDEV library to version 2.3.1.2 or later immediately
Identify all applications and systems utilizing vulnerable iccDEV library versions
Restrict ICC profile processing to trusted sources only until patching is complete
Implement input validation to reject ICC profiles from untrusted sources

Patch Information

The vulnerability has been patched in iccDEV version 2.3.1.2. The fix modifies the validation logic in CIccTagLut16::Validate() to use channel counts as read from the LUT structure (m_nInput and m_nOutput) rather than deriving them from the profile header. This ensures that validation loops operate within the bounds of actually allocated memory.

The patch is available through the following commits:

For additional details, refer to the GitHub Security Advisory GHSA-9q9c-699q-xr2q and GitHub Issue #397.

Workarounds

No known workarounds are available for this vulnerability according to the vendor advisory
As a defense-in-depth measure, restrict ICC profile processing to files from trusted sources only
Consider implementing sandboxing for applications that must process untrusted ICC profiles
Deploy application-level controls to validate ICC profile structure before passing to the iccDEV library

bash

# Verify iccDEV library version
# Check installed version in your build environment
grep -r "ICCDEV_VERSION" /path/to/iccDEV/include/

# Update to patched version
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