CVE-2025-48072: OpenEXR Buffer Overflow Vulnerability

CVE-2025-48072 Overview

CVE-2025-48072 is a heap-based buffer overflow vulnerability affecting OpenEXR, the specification and reference implementation of the EXR file format widely used in the motion picture and visual effects industry. The vulnerability exists in version 3.3.2 and occurs during read operations when decompressing DWAA-packed scan-line EXR files containing maliciously crafted chunks. Bad pointer math during the decompression process enables an attacker to trigger an out-of-bounds read condition.

Critical Impact

Attackers can exploit this vulnerability by crafting malicious EXR files that, when processed by vulnerable OpenEXR implementations, cause heap buffer overflows leading to potential information disclosure and denial of service conditions.

Affected Products

• OpenEXR version 3.3.2
• Applications and libraries built against OpenEXR 3.3.2
• Visual effects and image processing pipelines using vulnerable OpenEXR versions

Discovery Timeline

• 2025-07-31 - CVE-2025-48072 published to NVD
• 2025-08-13 - Last updated in NVD database

Technical Details for CVE-2025-48072

Vulnerability Analysis

This vulnerability is classified as CWE-125 (Out-of-Bounds Read), manifesting during the DWAA (DWA with Alpha) compression decompression workflow in OpenEXR. The root cause stems from improper pointer arithmetic when handling scan-line data blocks. When a maliciously forged chunk is encountered during decompression, the library performs incorrect pointer calculations that can result in memory access beyond allocated buffer boundaries.

The attack requires local access and user interaction—specifically, a victim must open or process a specially crafted EXR file. Successful exploitation can lead to high confidentiality and availability impacts, potentially exposing sensitive memory contents or causing application crashes.

Root Cause

The vulnerability originates from bad pointer math in the DWAA decompression routines. Specifically, the DwaCompressor_setupChannelData function's return value was not being properly validated before subsequent operations continued. Additionally, the pointer alignment logic in internal_dwa_decoder.h contained flawed arithmetic that could lead to misaligned memory accesses and buffer overruns when processing malformed chunk data.

Attack Vector

The attack vector is local, requiring an attacker to deliver a malicious EXR file to a victim system. This could occur through various channels including email attachments, file sharing services, or compromised media asset repositories. When a vulnerable application (such as image editors, 3D rendering software, or VFX compositing tools) attempts to open and decompress the malicious file, the heap buffer overflow is triggered.

// Security patch in src/lib/OpenEXRCore/internal_dwa_compressor.h - Fix bad pointer math
    if (version > 2) { return EXR_ERR_BAD_CHUNK_LEADER; }

    rv = DwaCompressor_setupChannelData (me);
+    if (rv != EXR_ERR_SUCCESS) { return rv; }

    //
    // Uncompress the UNKNOWN data into _planarUncBuffer[UNKNOWN]

Source: GitHub Commit Details

// Security patch in src/lib/OpenEXRCore/internal_dwa_decoder.h - Fix bad pointer math
    // Allocate a temp aligned buffer to hold a rows worth of full
    // 8x8 half-float blocks
    //
    rowBlockHandle = alloc_fn (
        (size_t) numComp * (size_t) numBlocksX * 64 * sizeof (uint16_t) +
        _SSE_ALIGNMENT);
    if (!rowBlockHandle) return EXR_ERR_OUT_OF_MEMORY;

-    rowBlock[0] = (uint16_t*) rowBlockHandle;
-
-    for (int i = 0; i < _SSE_ALIGNMENT; ++i)
-    {
-        if (((uintptr_t) (rowBlockHandle + i) & _SSE_ALIGNMENT_MASK) == 0)
-            rowBlock[0] = (uint16_t*) (rowBlockHandle + i);
-    }
+    rowBlock[0] = (uint16_t*) simd_align_pointer (rowBlockHandle);

    for (int comp = 1; comp < numComp; ++comp)
        rowBlock[comp] = rowBlock[comp - 1] + numBlocksX * 64;

Source: GitHub Commit Details

Detection Methods for CVE-2025-48072

Indicators of Compromise

• Unexpected application crashes when opening EXR files, particularly those using DWAA compression
• Memory corruption indicators in application logs during EXR file processing
• Anomalous EXR files with unusual chunk structures or header values in media asset repositories

Detection Strategies

• Implement file integrity monitoring for EXR files entering production pipelines from external sources
• Deploy application crash monitoring to detect repeated failures during EXR decompression operations
• Utilize memory sanitizers (AddressSanitizer, Valgrind) in development environments to catch out-of-bounds read attempts
• Scan software inventories for OpenEXR version 3.3.2 dependencies

Monitoring Recommendations

• Monitor VFX and rendering application logs for segmentation faults or heap corruption errors during EXR processing
• Implement endpoint detection rules to identify abnormal memory access patterns in applications using OpenEXR
• Track file provenance for EXR assets entering trusted environments from external vendors or contractors

How to Mitigate CVE-2025-48072

Immediate Actions Required

• Upgrade OpenEXR to version 3.3.3 or later immediately
• Audit all applications and libraries that depend on OpenEXR for vulnerable versions
• Quarantine untrusted EXR files until systems are patched
• Implement additional input validation for EXR files from external sources

Patch Information

The OpenEXR project has addressed this vulnerability in version 3.3.3. The fix ensures proper validation of the DwaCompressor_setupChannelData return value before continuing decompression operations and replaces the flawed manual pointer alignment loop with a dedicated simd_align_pointer helper function.

For detailed patch information, refer to the GitHub Security Advisory GHSA-4r7w-q3jg-ff43 and the OpenEXR v3.3.3 Release.

Workarounds

• Restrict processing of DWAA-compressed EXR files until the patch is applied
• Implement sandboxing for EXR processing applications to limit impact of potential exploitation
• Pre-validate EXR files using updated tools before processing in production environments

# Verify OpenEXR version and upgrade
# Check current version
pkg-config --modversion OpenEXR

# Update to patched version (example for systems using vcpkg)
vcpkg upgrade openexr

# Or rebuild from source using the patched release
git clone https://github.com/AcademySoftwareFoundation/openexr.git
cd openexr
git checkout v3.3.3
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build
sudo cmake --install build