---
id: CVE-2026-88052
title: Tesseract is an open source OCR engine
summary: >-
  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. u…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'
cwe:
  - CWE-129
  - CWE-787
vendor: tesseract-ocr
product: tesseract_ocr
affected:
  - tesseract_ocr <= 5.5.3
published: '2026-09-10'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T16:21:10.677'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-88052'
references:
  - url: >-
      https://github.com/tesseract-ocr/tesseract/commit/2d04d640db2e8c7e3bab2369d599343b5a8b8443
    label: security-advisories@github.com
  - url: >-
      https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-2hm8-q5c7-c373
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
epss: 0.00183
epssPercentile: 0.06991
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-11T16:48:33.418715Z'
ingestedAt: '2026-09-14T13:09:43.077Z'
---

## Overview

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.

## Affected

- `tesseract_ocr <= 5.5.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.