CVE-2024-56826: OpenJPEG Buffer Overflow Vulnerability

CVE-2024-56826 Overview

A heap buffer overflow vulnerability was discovered in the OpenJPEG project that affects the opj_decompress utility. When certain options are specified during JPEG 2000 image decompression, a heap buffer overflow condition can be triggered. This memory corruption flaw can lead to an application crash or other undefined behavior, potentially impacting systems that process untrusted JPEG 2000 images.

Critical Impact

Local attackers with user interaction can trigger a heap buffer overflow in OpenJPEG's decompression utility, leading to application crashes and potential denial of service conditions.

Affected Products

• OpenJPEG library (openjpeg)
• Systems using opj_decompress utility
• Linux distributions with bundled OpenJPEG packages (Red Hat, Debian)

Discovery Timeline

• 2025-01-09 - CVE CVE-2024-56826 published to NVD
• 2025-11-03 - Last updated in NVD database

Technical Details for CVE-2024-56826

Vulnerability Analysis

This vulnerability is classified as CWE-122 (Heap-based Buffer Overflow). The flaw exists in the tile-part indexing functionality within OpenJPEG's JPEG 2000 codec implementation. When processing malformed or specially crafted JPEG 2000 files, the opj_j2k_add_tlmarker() function in src/lib/openjp2/j2k.c fails to properly validate that the current tile-part number is within bounds before accessing the tile-part index array.

The vulnerability requires local access and user interaction to exploit, as an attacker must convince a user to process a malicious JPEG 2000 file using the opj_decompress utility with specific options. While exploitation leads primarily to denial of service through application crashes, heap buffer overflows can potentially lead to more severe consequences depending on memory layout and system configuration.

Root Cause

The root cause lies in insufficient bounds checking in the opj_j2k_add_tlmarker() function. Prior to the fix, the code only verified that the tp_index pointer was non-null before writing to the array at position l_current_tile_part. However, there was no validation to ensure that l_current_tile_part was smaller than the allocated array size (nb_tps). This missing boundary check allows writes beyond the allocated heap buffer when processing malformed tile-part data.

Attack Vector

The attack requires local access with low privileges and user interaction. An attacker must:

1. Craft a malicious JPEG 2000 file with corrupted tile-part metadata
2. Convince a user to decompress the file using opj_decompress with specific options
3. The malformed tile-part number causes an out-of-bounds write to the heap buffer

    if (type == J2K_MS_SOT) {
        OPJ_UINT32 l_current_tile_part = cstr_index->tile_index[tileno].current_tpsno;

-        if (cstr_index->tile_index[tileno].tp_index) {
+        if (cstr_index->tile_index[tileno].tp_index &&
+                l_current_tile_part < cstr_index->tile_index[tileno].nb_tps) {
            cstr_index->tile_index[tileno].tp_index[l_current_tile_part].start_pos = pos;
        }

Source: GitHub OpenJPEG Commit

Detection Methods for CVE-2024-56826

Indicators of Compromise

• Unexpected crashes of applications using OpenJPEG library during JPEG 2000 processing
• Core dumps or segmentation faults in opj_decompress utility
• Abnormal memory consumption patterns when processing JPEG 2000 files
• Application logs showing errors related to tile-part parsing in J2K files

Detection Strategies

• Monitor for crashes in opj_decompress or applications linking against OpenJPEG
• Implement file integrity monitoring for OpenJPEG library files to detect unauthorized modifications
• Deploy application-level logging to capture JPEG 2000 processing errors and crashes
• Use memory sanitizers (ASan, Valgrind) in development environments to detect heap overflows

Monitoring Recommendations

• Enable crash reporting and log collection for systems processing JPEG 2000 images
• Monitor for unusual file processing activity targeting image decompression utilities
• Implement alerting for repeated application crashes involving OpenJPEG components
• Review system logs for segmentation faults associated with image processing workflows

How to Mitigate CVE-2024-56826

Immediate Actions Required

• Update OpenJPEG to a patched version that includes commit e492644fbded4c820ca55b5e50e598d346e850e8
• For Red Hat systems, apply the security errata RHSA-2025:7309
• For Debian systems, refer to the Debian LTS Announcement for patched package versions
• Restrict access to systems running opj_decompress to trusted users only

Patch Information

The vulnerability has been addressed in the upstream OpenJPEG repository. The fix adds proper bounds checking to validate that l_current_tile_part is less than nb_tps before accessing the tile-part index array. Security patches are available from:

• GitHub OpenJPEG Commit
• Red Hat Security Errata RHSA-2025:7309
• Debian LTS Security Updates

For detailed tracking, refer to Red Hat Bugzilla #2335172 and the GitHub Issue #1563.

Workarounds

• Avoid processing untrusted JPEG 2000 files until patching is complete
• Implement input validation to reject malformed JPEG 2000 files before processing
• Run opj_decompress in a sandboxed environment with restricted permissions
• Use alternative image processing libraries for handling untrusted JPEG 2000 content where possible

# Check current OpenJPEG version on Linux systems
opj_decompress -h 2>&1 | head -n 2

# For Red Hat/CentOS systems, update OpenJPEG packages
sudo yum update openjpeg2

# For Debian/Ubuntu systems, update OpenJPEG packages
sudo apt-get update && sudo apt-get upgrade libopenjp2-7