Tesseract is an open source OCR engine. In version 5.5.3 and earlier, the callback form of GenericVector::read in src/ccutil/genericvector.h reads the independent int32 fields reserved and sizeused from a .traineddata model without a cap or an invariant check. reserve(reserved) allocates the backing array, but the callback loop writes sizeused elements. A crafted TESSDATAINTTEMP component with versionid 4 or later can therefore set reserved to a small value and sizeused to a large value when fontinfotable.read(fp, readinfo) is called from src/classify/intproto.cpp, causing a heap out-of-bounds write of FontInfo structures, heap corruption, a crash, or potentially controlled corruption. No fixed release is available as of this review.

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, FullyConnected::DeSerialize in src/lstm/fullyconnected.cpp does not validate the deserialized layer scalars ni and no against the weight-matrix dimensions. During FullyConnected::Forward, MatrixDotVector in src/lstm/weightmatrix.cpp writes w.dim1() results into templine, which is sized from no, and reads w.dim2() minus one inputs from currinput, which is sized from ni. A crafted .traineddata NTSOFTMAX layer can therefore use inconsistent dimensions to cause a heap out-of-bounds write and read on the default LSTM engine, resulting in heap corruption, a crash, information disclosure, or potentially controlled corruption. No fixed release is available as of this review.

Tesseract is an open source OCR engine. Prior to 5.5.3, a crafted .traineddata LSTM model component loaded through Tesseract's deserializer can cause an unchecked signed integer multiplication in Convolve::DeSerialize in src/lstm/convolve.cpp to wrap the convolution output-channel count, undersizing the forward-pass output buffer while writes use the unwrapped element count and causing a heap out-of-bounds write during OCR recognition. This issue is fixed in version 5.5.3.

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, Plumbing::DeSerialize in src/lstm/plumbing.cpp rejects excessively large network stacks but accepts a zero-length stack for NTSERIES, NTPARALLEL, or NTREVERSED layers in a crafted .traineddata model. During LSTMRecognizer initialization in src/lstm/lstmrecognizer.cpp, CacheXScaleFactor(XScaleFactor()) reaches Series::CacheXScaleFactor in src/lstm/series.cpp, which dereferences stack[0] on the empty vector and invokes a virtual method through an invalid Network pointer. This causes a deterministic crash and denial of service at model load. No fixed release is available as of this review.