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CVE-2026-88049— Tesseract: Heap out-of-bounds write in LSTM::Forward via na_/gate-matrix dimension mismatch

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及之前版本存在缓冲区错误漏洞，该漏洞源于NetworkIO::WriteTimeStepPart和NetworkIO::AddTimeStepPart缺少边界检查，特制NT_LSTM层可使ns_远大于na_，导致默认LSTM引擎在首次识别步骤发生堆越界写入，可能造成堆损坏、崩溃或受控破坏。

CVSS 8.6 · High EPSS 0.15% · P4 Updated Sep 11, 2026

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

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-2026-88049

Vulnerability Information

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Vulnerability Title

Tesseract: Heap out-of-bounds write in LSTM::Forward via na_/gate-matrix dimension mismatch

Source: CVE Program / CVE List V5

Vulnerability Description

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, prior .traineddata hardening added bounds checks to NetworkIO::CopyTimeStepGeneral and NetworkIO::Randomize in src/lstm/networkio.cpp but left NetworkIO::WriteTimeStepPart and NetworkIO::AddTimeStepPart unchecked. In LSTM::Forward in src/lstm/lstm.cpp, source_ is sized from the independently deserialized na_ field while the WriteTimeStepPart count is ns_, which comes from the CI gate WeightMatrix dim1() value. A crafted NT_LSTM layer can make ns_ much larger than na_, causing a heap out-of-bounds write during the first recognition step on the default LSTM engine and resulting in 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:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Source: CVE Program / CVE List V5

Vulnerability Type

跨界内存写

Source: CVE Program / CVE List V5

Vulnerability Title

tesseract-ocr Tesseract 缓冲区错误漏洞

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-2026-88049

#	POC Description	Source Link	Shenlong Link

AI-Generated POC Premium

No public POC found.

III. Intelligence Information for CVE-2026-88049

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Patches & Fixes for CVE-2026-88049 (1)

🔗 Validate LSTM gate matrix dimensions against na_/no_ at load · tesseract-ocr/tesseract@b494ac1 · GitHub x_refsource_MISC

Vendor Advisories for CVE-2026-88049 (1)

🔗 Heap out-of-bounds write in LSTM::Forward via na_/gate-matrix dimension mismatch · Advisory · tesseract-ocr/tesseract · GitHub Read full article x_refsource_CONFIRM

https://www.cve.org/CVERecord?id=CVE-2026-88049

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

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-2026-88052	7.8 HIGH	Tesseract: Heap out-of-bounds write in UNICHARSET::load_via_fgets via count/insert desynch
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-787