MAT File I/O Library / News: Recent posts

Changes in matio 1.5.30 (6 January 2026)

• Fixed const-correctness of input arguments of Mat_VarCreateStruct
• Deprecated usage of Mat_VarCreateStruct in favor of Mat_VarCreateStruct2 (CVE-2025-50343)
• Several other fixes, for example for memory leaks

Changes in matio 1.5.29 (10 November 2025)

• Fixed printing rank-1-variable in Mat_VarPrint
• Fixed array index out of bounds in Mat_VarPrint when printing UTF-8 character data (CVE-2025-2337)
• Fixed heap-based buffer overflow in strdup_vprintf (CVE-2025-2338)
• Changed Mat_VarPrint to print all values of rank-2-variable
• Confirmed compatibility with HDF5 v2.0.0
• autoconf: Updated config.sub and config.guess
• CMake: Enabled dependency resolution via Conan 2.x for CMake ≥ 3.24
• CMake: Enabled parallel testing
• CMake: Deprecated option MATIO_USE_CONAN:BOOL for Conan 1.x
• Several other fixes, for example for access violations in Mat_VarPrint

Changes in matio 1.5.28 (30 October 2024)

• Fixed bug writing MAT_T_INT8/MAT_T_UINT8 encoded character array to compressed v5 MAT file (regression of v1.5.12)
• Fixed bug reading all-zero sparse array of v4 MAT file (regression of v1.5.18)
• Updated C99 snprintf.c
• CMake: Enabled testing via option MATIO_BUILD_TESTING:BOOL
• CMake: Fixed build with Visual Studio ≥ 17.10 via option MATIO_USE_CONAN:BOOL and Conan 1.x
• Several other fixes, for example for access violations in Mat_VarPrint

Changes in matio 1.5.27 (20 April 2024)

• Fixed const-correctness of input arguments of API functions
• Fixed const-correctness of return type of Mat_GetDir (from char** to char* const*)
• Fixed bug duplicating function class (with deep copy) in Mat_VarDuplicate
• Fixed little endian detection for __aarch64__ (contributed by @maltelenz)
• Fixed LFS support on MinGW 64-bit builds (contributed by @chris-se)
• Fixed support of Unicode filenames on Windows (contributed by @chris-se)
• Fixed detection of HDF5 version for UTF-8 based file name of HDF5 MAT file (contributed by @chris-se)
• Fixed stack-based buffer overflow when reading (crafted) HDF5 MAT file
• Fixed build on Solaris
• Fixed build with Rust bindings and LLVM ≥ 16
• CMake: Fixed MinGW linker error with libc (regression of v1.5.24) (contributed by @chris-se)
• CMake: Enabled static analysis with Cppcheck via option MATIO_ENABLE_CPPCHECK:BOOL

Changes in 1.5.26 (12 November 2023)

• Fixed testsuite (regression of v1.5.25)

Changes in 1.5.25 (10 November 2023)

• Fixed reading struct array with null padded class name from HDF5 MAT file
• Fixed memory leak in Mat_VarFree for function class
• CMake: Silence MSVC compiler warnings

Changes in 1.5.24 (28 October 2023)

• Added predicated iteration API functions Mat_VarReadNextInfoPredicate and Mat_VarReadNextPredicate to speed-up reading variables from HDF5 MAT file
• Added new API function Mat_GetFileAccessMode to retrieve the file access mode of a MAT file
• Changed: Mat_VarDelete returns error if MAT file is opened in read-only mode
• Changed: Reduced memory foot-print of matvar_t.internal
• Fixed read performance of cell/struct array from HDF5 MAT file
• Fixed reference counting of HDF5 MAT file in Mat_VarDuplicate
• Fixed file access mode of created v4 MAT file
• Fixed read performance of Mat_GetDir for HDF5 MAT file
• Fixed bug reading struct array from v5 MAT file
• Fixed bug adding field to struct array of v5 MAT file
• Fixed heap-based buffer overflow when reading HDF5 MAT file
• Confirmed compatibility with HDF5 v1.14.x
• autoconf: Enabled system extensions
• autoconf: Fixed getopt_long check
• autoconf: Fixed pkg-config file for static linking
• CMake: Updated cmake-conan to version 0.18.1
• CMake: Fixed version comparison
• CMake: Fixed properties for CMake < 3.11
• CMake: Fixed linker error on OpenBSD
• CMake: Fixed checks of linker options
• Several other fixes, for example for memory leaks

Changes in 1.5.22 (25 March 2022)

• Added support for reading large MAT file
• Updated cmake-conan to version 0.17.0
• Fixed CMake build with Conan (MATIO_USE_CONAN:BOOL=ON)
• Fixed data type when reading 16-bit character data from HDF5 MAT file
• Fixed heap-based buffer overflows when reading (crafted) MAT file (CVE-2020-36428, CVE-2021-36977)
• Confirmed compatibility with HDF5 v1.13.0 and v1.13.1
• Several other fixes, for example for memory leaks

Changes in 1.5.21 (25 March 2021)

• Fixed: Avoid usage of strlen when creating MAT_T_UTF8 encoded character array (regression of v1.5.20)
• Fixed reading of compression flag from HDF5 MAT file

Changes in 1.5.20 (21 March 2021)

• Added support for writing MAT_T_UTF8 encoded character array to HDF5 MAT file (by conversion to UTF-16 if in BMP)
• Updated cmake-conan to version 0.16.1
• Fixed bug with size_t arguments of logging function calls
• Fixed bug reading past EOF from (crafted) MAT file
• Fixed bug writing MAT_T_UTF8 encoded character array to v5 MAT file
• Fixed printing of MAT_T_UTF8 encoded character array
• Several other fixes, for example for memory leaks

Changes in 1.5.19 (6 November 2020)

• Fixed support for CMake (>= v3.19.0) build system
• Fixed bug reading variable from v4 MAT file (regression of v1.5.18)

Changes in 1.5.18 (17 September 2020)

• Added support of HDF5 v1.12.x
• Added support for UTF-8 encoded file name on Windows (MSVC) (requires HDF5 >= v1.11.6 for HDF5 MAT file)
• Added support for reading uncompressed v5 MAT file generated by SWAN
• Added error codes to public interface
• Added support for CMake build system
• Fixed read performance of numeric array from compressed v5 MAT file
• Fixed support for VS2005 and VS2008 (MSVC) (regression of v1.5.15)
• Fixed mktemp linker warning when using GNU linker
• Fixed bug writing struct array to uncompressed v5 MAT file on big endian architecture (regression of v1.5.10)
• Fixed bug writing cell array to uncompressed v5 MAT file on big endian architecture
• Fixed bug reading variable name from v4 MAT file (CVE-2019-17533)
• Fixed bug reading dimensions from (crafted) compressed v5 MAT file (CVE-2019-20017, CVE-2019-20018, CVE-2019-20020, CVE-2019-20052)

Changes in 1.5.17 (18 July 2019)

• Fixed bug reading struct array with packed field names from v5 MAT file
• Fixed bug reading past EOF from (crafted) uncompressed v5 MAT file

Changes in 1.5.16 (25 June 2019)

• Fixed error handling on integer addition/multiplication overflows (CVE-2019-13107) found with Mayhem by ForAllSecure

Changes in 1.5.15 (29 March 2019)

• Added new API function Mat_GetHeader to retrieve header string of a MAT file
• Fixed integer multiplication overflows when calculating total number of elements from (crafted) MAT file
• Fixed bug reading character array from (compressed) v5 MAT file (regression of v1.5.14)
• Fixed number of variables for repeated calls of Mat_GetDir
• Fixed memory leak in Mat_VarFree for function class

Changes in 1.5.14 (11 March 2019)

• Deprecated usage of Mat_VarWriteInfo/Mat_VarWriteData in favor of Mat_VarWrite/Mat_VarWriteAppend
• Fixed bug reading dimensions from (crafted) compressed v5 MAT file
• Fixed bug reading name (> 24 characters) from v5 MAT file (regression of v1.5.13)
• Fixed bug printing datatype in Mat_VarPrint

Changes in 1.5.13 (22 October 2018)

• Fixed bug calculating size for zero-rank variables in Mat_VarGetSize
• Fixed bug reading dimensions from (crafted) v5 MAT file
• Fixed bug reading tag and class from (crafted) v5 MAT file
• Fixed integer multiplication overflows
• Fixed HDF5 compatibility in Mat_Open and Mat_Create for HDF5 > v1.10.1

Changes in 1.5.12 (9 March 2018)

• Updated Mat_VarWriteAppend: Added support to append a variable to a previously written struct array in HDF5 MAT file
• Fixed bug reading MAT_T_UINT16 encoded character array from HDF5 MAT file
• Fixed bug reading MAT_T_UTF16 encoded character array from compressed v5 MAT file
• Fixed bug writing MAT_T_UTF16 encoded character array to HDF5 MAT file
• Fixed buffer overflow in Mat_VarGetCells/Mat_VarGetStructs

Changes in 1.5.11 (22 October 2017)

• Added new API function Mat_VarWriteAppend to append a numeric array to a previously written variable in HDF5 MAT file
• Fixed bug calculating sizes of cell/struct array with empty cells/fields in Mat_VarGetSize
• Fixed bug writing cell/struct array with empty cells/fields to v5 MAT file
• Fixed bug writing cell/struct array with empty cells/fields to HDF5 MAT file
• Fixed read performance of cell/struct array with empty cells/fields from v5 MAT file
• Fixed read performance of numeric array from uncompressed v5 MAT file
• Fixed testsuite (if configured with the MATLAB application)
• Updated man pages

Changes in 1.5.10 (14 February 2017)

• Added new API function Mat_GetDir to retrieve all variable names of a MAT file
• Fixed performance of repeated calls to Mat_VarWrite (broken by v1.5.7)
• Fixed bugs reading (hyperslabs of) numeric arrays where the variable data type differs from the desired output data type
• Increased testsuite coverage

Changes in 1.5.9 (22 October 2016)

• Fixed resource leak when reading character data from HDF5 MAT file
• Fixed bug writing struct to HDF5 MAT file: Mat_VarWrite never returned 0 on success
• Fixed bug writing sparse logical array to HDF5 MAT file
• Fixed bug calculating array sizes of structs, cells, complex and sparse arrays in Mat_VarGetSize
• Fixed bug duplicating sparse array with empty data in Mat_VarDuplicate
• Fixed segmentation fault when reading compressed v5 MAT file with opaque class
• Updated support of HDF5 v1.10.x: No longer depend on deprecated v1.8.x symbols

Changes in 1.5.8 (30 June 2016)

• Fixed bug writing array to v4 MAT files on big endian architecture (broken by v1.5.7)

Changes in 1.5.7 (22 June 2016)

• Added support for MAT_T_UTF16 when reading character array from v5 MAT file
• Added support of HDF5 v1.10.x (with deprecated v1.8.x symbols exported)
• Added warning on unsupported character data types when reading v5 MAT file
• Added error check if variable already exists when writing to MAT file
• Fixed support of custom log functions: Moved log levels to the public interface
• Fixed bug creating v4 and v5 MAT file: Open in write+update mode
• Fixed bug creating v5 and HDF5 MAT file: Set BOF marker to 128
• Fixed bug in Mat_VarDelete: Rewind file before looping over variables
• Fixed bug writing cell array with empty struct fields to compressed v5 MAT file
• Fixed bug reading empty character array from HDF5 MAT file
• Fixed bug iterating through links in a group of HDF5 MAT file
• Fixed bug iterating on #subsystem# group of HDF5 MAT file
• Fixed compilation out of source directory
• Fixed C++ compilation on MinGW
• Restructured testsuite
• Fixed testsuite if hdf5 dependency is missing
• Increased testsuite coverage
• Various fixes for variable scopes that cause compilers to issue diagnostics

Changes in 1.5.6 (23 February 2016)

• Fixed bug writing array to v4 MAT files on big endian architecture
• Fixed bug writing header with more than 127 characters to v5 or HDF5 MAT files
• Increased testsuite coverage

Changes in 1.5.5 (19 February 2016)

• Added support of reading sparse array from v4 MAT files
• Added support of writing sparse array to v4 MAT files
• Added support of writing character array to v4 MAT files
• Added support of autogen.sh on Darwin
• Added missing Visual Studio project files for test_mat
• Added missing Visual Studio resource file
• Enabled C++ compilation
• Updated snprintf.c to C99 snprintf v1.1
• Increased testsuite coverage
• Fixed bug writing complex array to v4 MAT files
• Fixed bug writing cell containing a struct with fields but empty array to compressed v5 MAT files
• Fixed bug reading hyperslabs of cells and struct fields from compressed v5 MAT files (broken by v1.5.3)
• Fixed bug writing empty character array to uncompressed v5 MAT files
• Fixed bug reading cells and struct fields from HDF5 MAT files
• Fixed bug printing array dimensions in Mat_VarPrint on MinGW
• Fixed bug calculating array sizes of structs in Mat_VarGetSize
• Fixed bug duplicating sparse array in Mat_VarDuplicate
• Fixed testsuite if zlib/hdf5 dependencies are missing
• Several other fixes, especially for memory leaks