CVE-2025-48073

Summary

When reading a deep scanline image with a large sample count in reduceMemory mode, it is possible to crash a target application with a NULL pointer dereference in a write operation.

Details

In the ScanLineProcess::run_fill function, implemented in src/lib/OpenEXR/ImfDeepScanLineInputFile.cpp, the following code is used to write the fillValue in the sample buffer:

                switch (fills.type)
                {
                    case OPENEXR_IMF_INTERNAL_NAMESPACE::UINT:
                    {
                        unsigned int fillVal = (unsigned int) (fills.fillValue);
                        unsigned int* fillptr = static_cast<unsigned int*> (dest);

                        for ( int32_t s = 0; s < samps; ++s )
                            fillptr[s] = fillVal; // <--- POTENTIAL CRASH HERE
                        break;
                    }

However, when reduceMemory mode is enabled in the readDeepScanLine function in src/lib/OpenEXRUtil/ImfCheckFile.cpp, with large sample counts, the sample data will not be read, as shown below:

            // limit total number of samples read in reduceMemory mode
            //
            if (!reduceMemory ||
                fileBufferSize + bufferSize < gMaxBytesPerDeepScanline) // <--- CHECK ON LARGE SAMPLE COUNTS AND reduceMemory
            {
            // SNIP...
            try
                {
                    in.readPixels (y);
                }

Therefore, in those cases, the sample buffer would not be allocated, resulting in a potential write operation on a NULL pointer.

PoC

NOTE: please download the runfill_crash.exr file from the following link:

https://github.com/ShielderSec/poc/tree/main/CVE-2025-48073

1. Compile the exrcheck binary in a macOS or GNU/Linux machine with ASAN.
2. Open the runfill_crash.exr file with the following command:

exrcheck -m runfill_crash.exr

3. Notice that exrcheck crashes with ASAN stack-trace.

Impact

An attacker may cause a denial of service by crashing the application.

Summary

When reading a deep scanline image with a large sample count in reduceMemory mode, it is possible to crash a target application with a NULL pointer dereference in a write operation.

Details

In the ScanLineProcess::run_fill function, implemented in src/lib/OpenEXR/ImfDeepScanLineInputFile.cpp, the following code is used to write the fillValue in the sample buffer:

                switch (fills.type)
                {
                    case OPENEXR_IMF_INTERNAL_NAMESPACE::UINT:
                    {
                        unsigned int fillVal = (unsigned int) (fills.fillValue);
                        unsigned int* fillptr = static_cast<unsigned int*> (dest);

                        for ( int32_t s = 0; s < samps; ++s )
                            fillptr[s] = fillVal; // <--- POTENTIAL CRASH HERE
                        break;
                    }

However, when reduceMemory mode is enabled in the readDeepScanLine function in src/lib/OpenEXRUtil/ImfCheckFile.cpp, with large sample counts, the sample data will not be read, as shown below:

            // limit total number of samples read in reduceMemory mode
            //
            if (!reduceMemory ||
                fileBufferSize + bufferSize < gMaxBytesPerDeepScanline) // <--- CHECK ON LARGE SAMPLE COUNTS AND reduceMemory
            {
            // SNIP...
            try
                {
                    in.readPixels (y);
                }

Therefore, in those cases, the sample buffer would not be allocated, resulting in a potential write operation on a NULL pointer.

PoC

NOTE: please download the runfill_crash.exr file from the following link:

https://github.com/ShielderSec/poc/tree/main/CVE-2025-48073

1. Compile the exrcheck binary in a macOS or GNU/Linux machine with ASAN.
2. Open the runfill_crash.exr file with the following command:

exrcheck -m runfill_crash.exr

3. Notice that exrcheck crashes with ASAN stack-trace.

Impact

An attacker may cause a denial of service by crashing the application.

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. In version 3.3.2, when reading a deep scanline image with a large sample count in reduceMemory mode, it is possible to crash a target application with a NULL pointer dereference in a write operation. This is fixed in version 3.3.3.

These are all security issues fixed in the libIex-3_3-32-3.3.5-1.1 package on the GA media of openSUSE Tumbleweed.