CVE-2026-88052

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

HIGH
7.8
CVSS Score
Published: September 10, 2026 at 05:38 PM UTC
Updated: September 16, 2026 at 04:37 PM UTC
2 products affected across 1 vendorTesseract OcrOcr Tesseract Ocr

Using tesseract by tesseract-ocr?

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Severity
HIGH7.8
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

Description

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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHGitHub_M
Attack Vector
LOCAL
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-129CWE-787

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