{"id":"CVE-2025-48073","aliases":["GHSA-qhpm-86v7-phmm","PYSEC-2026-1748"],"title":"OpenEXR ScanLineProcess::run_fill NULL Pointer Write In \"reduceMemory\" Mode","summary":"OpenEXR ScanLineProcess::run_fill NULL Pointer Write In \"reduceMemory\" Mode","severity":"medium","vendor":"openexr","product":"openexr","ecosystem":"pip","affected":["openexr >= 3.3.2, < 3.3.3"],"patched":["openexr 3.3.3"],"published":"2025-07-31","updated":"2026-07-07","source":"OSV","sourceUrl":"https://osv.dev/vulnerability/GHSA-qhpm-86v7-phmm","references":[{"url":"https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-qhpm-86v7-phmm"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-48073"},{"url":"https://github.com/AcademySoftwareFoundation/openexr"},{"url":"https://github.com/ShielderSec/poc/tree/main/CVE-2025-48073"}],"tags":["osv","pip"],"epss":0.002,"epssPercentile":0.10076,"ingestedAt":"2026-07-08T18:25:52.431Z","slug":"CVE-2025-48073","body":"## Overview\n\n### Summary\n\nWhen 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.\n\n### Details\n\nIn 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:\n\n```cpp\n                switch (fills.type)\n                {\n                    case OPENEXR_IMF_INTERNAL_NAMESPACE::UINT:\n                    {\n                        unsigned int fillVal = (unsigned int) (fills.fillValue);\n                        unsigned int* fillptr = static_cast<unsigned int*> (dest);\n\n                        for ( int32_t s = 0; s < samps; ++s )\n                            fillptr[s] = fillVal; // <--- POTENTIAL CRASH HERE\n                        break;\n                    }\n```\n\nHowever, 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:\n\n```cpp\n            // limit total number of samples read in reduceMemory mode\n            //\n            if (!reduceMemory ||\n                fileBufferSize + bufferSize < gMaxBytesPerDeepScanline) // <--- CHECK ON LARGE SAMPLE COUNTS AND reduceMemory\n            {\n            // SNIP...\n            try\n                {\n                    in.readPixels (y);\n                }\n```\n\nTherefore, in those cases, the sample buffer would not be allocated, resulting in a potential write operation on a NULL pointer.\n\n### PoC\n\nNOTE: please download the `runfill_crash.exr` file from the following link:\n \nhttps://github.com/ShielderSec/poc/tree/main/CVE-2025-48073\n\n1. Compile the `exrcheck` binary in a macOS or GNU/Linux machine with ASAN.\n2. Open the `runfill_crash.exr` file with the following command:\n\n```\nexrcheck -m runfill_crash.exr\n```\n\n3. Notice that `exrcheck` crashes with ASAN stack-trace.\n\n### Impact\nAn attacker may cause a denial of service by crashing the application.\n\n## Affected packages\n\n- `openexr >= 3.3.2, < 3.3.3`\n\n## Remediation\n\nUpgrade to a patched release:\n\n- `openexr 3.3.3`","depth":"sunlit","depthScore":28,"depthScoreParts":{"impact":27.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}