What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-10 · updated 2026-09-14
• Weakness: CWE-787

Description

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 products

• tesseract-ocr tesseract: through 5.5.3

References

• https://github.com/tesseract-ocr/tesseract/commit/b494ac18925f9d9aff9ef5815475de9943ab19bf
• https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-jgq8-pprg-vc68
• https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-jgq8-pprg-vc68

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