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CVE-2026-88052— Tesseract: Heap out-of-bounds write in UNICHARSET::load_via_fgets via count/insert desynchronization

Quick assessment

Affected

tesseract-ocr tesseract

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

tesseract-ocr Tesseract是tesseract-ocr组织的一款可将图像文字转换为可编辑文本的光学字符识别组件。 tesseract-ocr Tesseract 5.5.3及之前版本存在安全漏洞，该漏洞源于src/ccutil/unicharset.cpp文件中的UNICHARSET::load_via_fgets函数将声明的unichar计数作为循环边界，并将id作为未检查索引访问unichars向量，当遇到空、重复或已可编码的表示时，id可能超出向量大小，导致在初始化过程中越界写入

CVSS 7.8 · High EPSS 0.18% · P8 Updated Sep 12, 2026

Possible ATT&CK Techniques 1 AI

T1202 · Indirect Command Execution

Affected Version Matrix 1

Vendor	Product	Version Range	Status
tesseract-ocr	tesseract	`<= 5.5.3`	affected

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I. Basic Information for CVE-2026-88052

Vulnerability Information

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Vulnerability Title

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

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

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

Source: CVE Program / CVE List V5

Vulnerability Type

对数组索引的验证不恰当

Source: CVE Program / CVE List V5

Vulnerability Title

tesseract-ocr Tesseract 输入验证错误漏洞

Source: CNNVD (China National Vulnerability Database)

Vulnerability Description

Source: CNNVD (China National Vulnerability Database)

CVSS Information

N/A

Source: CNNVD (China National Vulnerability Database)

Vulnerability Type

N/A

Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
tesseract-ocr	tesseract	<= 5.5.3	-

II. Public POCs for CVE-2026-88052

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-88052

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Patches & Fixes for CVE-2026-88052 (1)

🔗 Reject unicharset files whose inserts desync id from unichars · tesseract-ocr/tesseract@2d04d64 · GitHub Read full article x_refsource_MISC

Vendor Advisories for CVE-2026-88052 (1)

🔗 Heap out-of-bounds write in UNICHARSET::load_via_fgets via count/insert desynchronization · Advisory · tesseract-ocr/tesseract · GitHub Read full article x_refsource_CONFIRM

https://www.cve.org/CVERecord?id=CVE-2026-88052

Same Patch Batch · tesseract-ocr · 2026-09-10 · 8 CVEs total

CVE-2026-88049	8.6 HIGH	Tesseract: Heap out-of-bounds write in LSTM::Forward via na_/gate-matrix dimension mismatc
CVE-2026-88048	8.6 HIGH	Tesseract: Heap out-of-bounds write/read in FullyConnected::Forward via layer/weight-matri
CVE-2026-88047	8.6 HIGH	Tesseract: ReadNormProtos stack buffer overflow
CVE-2026-88051	8.6 HIGH	Tesseract: Heap out-of-bounds write in GenericVector<T>::read due to independent reserved/
CVE-2026-88053	8.6 HIGH	Tesseract: Heap out-of-bounds write in Classify::ReadIntTemplates via unvalidated counts i
CVE-2026-88050	6.9 MEDIUM	Tesseract: Out-of-bounds write in UnicharCompress via unvalidated recoder code values
CVE-2026-88054	6.9 MEDIUM	Tesseract: Denial of service via empty-stack dereference in Plumbing/Series at model load

IV. Related Vulnerabilities

Same product: tesseract

Same vendor: tesseract-ocr

Same weakness: CWE-129