tesseract-ocr Tesseract up to 5.5.3 FullyConnected Layer fullyconnected.cpp DeSerialize ni_/no_ heap-based overflow

Summaryinfo

A vulnerability classified as critical has been found in tesseract-ocr Tesseract up to 5.5.3. Affected by this vulnerability is the function FullyConnected::DeSerialize of the file src/lstm/fullyconnected.cpp of the component FullyConnected Layer. The manipulation of the argument ni_/no_ leads to heap-based overflow. This vulnerability is traded as CVE-2026-88048. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in tesseract-ocr Tesseract up to 5.5.3. This issue affects the function FullyConnected::DeSerialize of the file src/lstm/fullyconnected.cpp of the component FullyConnected Layer. The manipulation of the argument ni_/no_ with an unknown input leads to a heap-based overflow vulnerability. Using CWE to declare the problem leads to CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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 temp_line, which is sized from no_, and reads w.dim2() minus one inputs from curr_input, which is sized from ni_. A crafted .traineddata NT_SOFTMAX 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.

The advisory is shared at github.com. The identification of this vulnerability is CVE-2026-88048 since 09/09/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/10/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• tesseract-ocr

Name

• Tesseract

Version

• 5.5.0
• 5.5.1
• 5.5.2
• 5.5.3

Website

• Product: https://github.com/tesseract-ocr/tesseract/

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