CVE-2026-88052 PUBLISHED

Tesseract: Heap out-of-bounds write in UNICHARSET::load_via_fgets via count/insert desynchronization

Assigner: GitHub_M
Reserved: 09.09.2026 Published: 10.09.2026 Updated: 10.09.2026

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, UNICHARSET::load_via_fgets in src/ccutil/unicharset.cpp trusts the declared unichar count as a loop bound and uses id as an unchecked index into the unichars vector. unichar_insert_backwards_compatible can leave the vector unchanged for an empty, duplicate, or already-encodable representation, causing id to become larger than unichars.size(). Subsequent set_* calls and the write to unichars[id].properties.enabled then write UNICHAR_PROPERTIES beyond the vector during initialization in both the default LSTM and legacy engines, causing heap corruption, a crash, or potentially controlled corruption. No fixed release is available as of this review.

Metrics

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS Score: 7.8

Product Status

Vendor tesseract-ocr
Product tesseract
Versions
  • Version <= 5.5.3 is affected

References

Problem Types

  • CWE-129: Improper Validation of Array Index CWE
  • CWE-787: Out-of-bounds Write CWE