CVE-2026-21491: Color Iccdev Buffer Overflow Vulnerability

CVE-2026-21491 Overview

CVE-2026-21491 is a heap-based buffer overflow [CWE-122] affecting the iccDEV library, which provides tooling for working with International Color Consortium (ICC) color management profiles. The flaw resides in the CIccTagTextDescription class and is triggered when the library processes the unicode description field within a maliciously crafted ICC profile. Versions prior to 2.3.1.2 are affected. A user must open or process a crafted profile for exploitation to succeed, making applications that ingest ICC profiles (image viewers, color converters, print pipelines) the primary attack surface.

Critical Impact
Processing a crafted ICC profile can corrupt heap memory in CIccTagTextDescription, leading to application crashes and potential local code execution in the context of the user.

Affected Products

iccDEV library versions prior to 2.3.1.2
Applications linking against vulnerable iccDEV builds for ICC profile parsing
Color management pipelines and image processors that consume untrusted ICC profiles

Discovery Timeline

2026-01-06 - CVE-2026-21491 published to NVD
2026-01-12 - Last updated in NVD database

Technical Details for CVE-2026-21491

Vulnerability Analysis

The vulnerability is a unicode buffer overflow in the CIccTagTextDescription tag handler. ICC profiles store text descriptions in three encodings: ASCII, Unicode, and ScriptCode. The unicode segment carries a declared length followed by UTF-16 character data. When iccDEV parses this segment, it does not adequately validate that the declared unicode count is consistent with the remaining tag size or the allocated destination buffer. An attacker who controls the profile can declare a unicode length that exceeds the allocated heap region, causing the subsequent copy loop to write past the buffer boundary.

Because the corruption occurs on the heap, exploitation outcomes range from process termination to controlled overwrites of adjacent heap metadata or function pointers. The issue is classified under [CWE-122] Heap-based Buffer Overflow.

Root Cause

The root cause is missing or incorrect bounds checking on the unicode length field within the CIccTagTextDescription deserialization path. The library trusts attacker-controlled size values from the profile structure when computing copy lengths. The upstream fixes in commits 7c2cb71 and e91fe72 add validation around the unicode buffer handling before any write occurs.

Attack Vector

Exploitation requires local access and user interaction: a victim must open or hand a crafted .icc or .icm profile to an application that uses iccDEV. The attack does not require authentication. Successful exploitation impacts confidentiality and availability of the affected process, while integrity is not directly impacted per the published CVSS vector. The vulnerability cannot be triggered remotely without an intermediary application that ingests profiles, but image-processing services or document viewers that auto-parse embedded profiles can broaden the attack surface.

No proof-of-concept exploit is publicly available, and the vulnerability is not listed in the CISA Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2026-21491

Indicators of Compromise

Unexpected crashes or heap corruption errors in processes that parse ICC profiles, particularly those linking iccDEV below 2.3.1.2.
ICC profile files (.icc, .icm) containing oversized or malformed unicode description fields in desc or mluc tag structures.
Embedded ICC profiles inside images (PNG, JPEG, TIFF) sourced from untrusted senders or downloads.

Detection Strategies

Inventory applications and build artifacts that statically or dynamically link iccDEV, and flag versions below 2.3.1.2.
Scan file repositories and email gateways for ICC profile chunks with abnormally large unicode length declarations relative to file size.
Run fuzzing or differential parsing against iccDEV builds in staging to surface crash signatures consistent with the CIccTagTextDescription overflow.

Monitoring Recommendations

Collect crash telemetry from endpoints handling ICC profiles and alert on repeated faults in iccDEV symbols.
Monitor child-process creation and unusual memory access from image-processing utilities following file open events.
Log file-write and execution chains originating from color management workflows for retrospective hunting.

How to Mitigate CVE-2026-21491

Immediate Actions Required

Upgrade iccDEV to version 2.3.1.2 or later across all dependent applications and rebuild downstream binaries.
Identify vendor software that bundles iccDEV and apply vendor-provided updates as they are released.
Restrict opening ICC profiles from untrusted sources until patched builds are deployed.

Patch Information

Version 2.3.1.2 contains the fix. The relevant upstream changes are in commits 7c2cb71 and e91fe72. Tracking details are available in GitHub Issue #396 and the GitHub Security Advisory GHSA-4pv4-4x2x-6j88.

Workarounds

No vendor-supplied workarounds are available; upgrading to 2.3.1.2 is required.
As a compensating control, block delivery of ICC profile files from untrusted email and web sources at gateway layers.
Run color management workflows under least-privilege user accounts and application sandboxes to limit blast radius if exploitation occurs.

bash

# Verify the installed iccDEV version and locate vulnerable binaries
ldconfig -p | grep -i icc
strings /path/to/binary | grep -i "iccdev"
# Pull and build the patched release
git clone https://github.com/InternationalColorConsortium/iccDEV.git
cd iccDEV && git checkout v2.3.1.2