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

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-88052
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-10 18:18:14 UTC
Updated2026-09-10 19:54:25 UTC
DescriptionTesseract 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from [email protected]

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

Problem Types: CWE-129 | CWE-787 | CWE-129 CWE-129: Improper Validation of Array Index | CWE-787 CWE-787: Out-of-bounds Write

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Tesseract-ocr Tesseract affected <= 5.5.3 Not specified

References

ReferenceSourceLinkTags
github.com/tesseract-ocr/tesseract/security/advisories/GHSA-2hm8-q5c7-c373 [email protected] github.com
github.com/tesseract-ocr/tesseract/commit/2d04d640db2e8c7e3bab2369d59934... [email protected] github.com
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