CVE-2026-88049 — Tesseract: Heap out-of-bounds write in LSTM::Forward via na_/gate-matrix dimension mismatch

Description (CNA)

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, prior .traineddata hardening added bounds checks to NetworkIO::CopyTimeStepGeneral and NetworkIO::Randomize in src/lstm/networkio.cpp but left NetworkIO::WriteTimeStepPart and NetworkIO::AddTimeStepPart unchecked. In LSTM::Forward in src/lstm/lstm.cpp, source_ is sized from the independently deserialized na_ field while the WriteTimeStepPart count is ns_, which comes from the CI gate WeightMatrix dim1() value. A crafted NT_LSTM layer can make ns_ much larger than na_, causing a heap out-of-bounds write during the first recognition step on the default LSTM engine and resulting in heap corruption, a crash, or potentially controlled corruption. No fixed release is available as of this review.

Affected (CNA)

Vendor / product	Versions
tesseract-ocr / tesseract	affected <= 5.5.3

CWE

CWE-787

References

ADP enrichment

CISA-ADP

No English description supplied.

https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-jgq8-pprg-vc68