CVE-2026-88051

Tesseract: Heap out-of-bounds write in GenericVector<T>::read due to independent reserved/size_used_ fields

Published Sep 10, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed

Description

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, the callback form of GenericVector::read in src/ccutil/genericvector.h reads the independent int32 fields reserved and size_used_ from a .traineddata model without a cap or an invariant check. reserve(reserved) allocates the backing array, but the callback loop writes size_used_ elements. A crafted TESSDATA_INTTEMP component with version_id 4 or later can therefore set reserved to a small value and size_used_ to a large value when fontinfo_table_.read(fp, read_info) is called from src/classify/intproto.cpp, causing a heap out-of-bounds write of FontInfo structures, heap corruption, a crash, or potentially controlled corruption. No fixed release is available as of this review.

Analysis

Technical impact

The vulnerability involves an out‑of‑bounds heap write in the GenericVector::read function of the Tesseract OCR engine. It occurs when the function reads two independent integer fields, reserved and size_used_, from a .traineddata file without validating that the allocated buffer is large enough for size_used a backing array based on the reserved value but proceeds to write size_used_ FontInfo structures, overrunning the buffer and corrupting adjacent heap objects. This can cause a crash or, if exploited, controlled memory corruption and is a classic heap buffer overflow (CWE‑787).

Affected Systems

The affected product is the Tesseract OCR engine, version 5.5.3 and all earlier releases. No newer releases have a fix at the time of this review.

Risk and Exploitability

The CVSS base score of 8.6 indicates high severity. The vulnerability requires a crafted .traineddata file with a version_id of 4 or later. Attackers are most likely to supply a malicious model to an OCR service that loads user files, such as a web‑based OCR API or and the vulnerability is not listed in CISA KEV, but the lack of a patch and the potential for heap corruption make the risk significant.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

tesseract-ocr

tesseract

affected

Version	Status	Constraints
`<= 5.5.3`	affected	—

Configuration 1 [-]

cpe:2.3:a:tesseract-ocr:tesseract_ocr:*:*:*:*:*:*:*:*

No data.

Vendor Product Versions

Tesseract Project

Tesseract

Version	Status	Scheme	Platform
`[0,5.5.3]`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the patch from commit 56e09ca12e751623fe796ce1554ce704bffd2ef0 once a new release is available.
Add validation logic that ensures the reserved value is not smaller than size_used_ before allocating or writing, and reject .traineddata files that violate this invariant.
Execute Tesseract OCR inside a sandbox or low‑privilege container, restricting file permissions so that any heap corruption cannot affect the broader system.

Generated by OpenCVE AI on September 10, 2026 at 23:49 UTC.

Tracking

Advisories

Source	ID	Title
Ubuntu USN	USN-8882-1	Tesseract vulnerabilities

Metrics

Attack Vector Local

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact High

Vulnerable System Integrity Impact High

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact High

Integrity Impact High

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.167% probability within 30 days)

Exploitation poc

Automatable no

Technical Impact total

References

Link	Providers
https://github.com/tesseract-ocr/tesseract/commit/56e09ca12e751623fe796ce1554ce704bffd2ef0
https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-88qp-4g94-3rf3
https://nvd.nist.gov/vuln/detail/CVE-2026-88051
https://www.cve.org/CVERecord?id=CVE-2026-88051

History

Sep 16, 2026 4:45 PM First appearance in the feed. Affected versions updated. Affected vendors updated. Scoring metrics updated View changes

Type	Values Removed	Values Added
First Time appeared		Tesseract-ocr Tesseract-ocr tesseract Ocr
CPEs		cpe:2.3:a:tesseract-ocr:tesseract_ocr::::::::
Vendors & Products		Tesseract-ocr Tesseract-ocr tesseract Ocr
Metrics	cvssV3_1 `{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}`	cvssV3_1 `{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'}`

Sep 15, 2026 3:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}`

Sep 13, 2026 7:45 PM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Tesseract Project Tesseract Project tesseract
Vendors & Products		Tesseract Project Tesseract Project tesseract

Sep 12, 2026 12:15 AM Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
References		https://nvd.nist.gov/vuln/detail/CVE-2026-88051 https://www.cve.org/CVERecord?id=CVE-2026-88051
Metrics	threat_severity `None`	cvssV3_1 `{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H'}` threat_severity `Important`

Sep 10, 2026 5:45 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Tesseract is an open source OCR engine. In version 5.5.3 and earlier, the callback form of GenericVector::read in src/ccutil/genericvector.h reads the independent int32 fields reserved and size_used_ from a .traineddata model without a cap or an invariant check. reserve(reserved) allocates the backing array, but the callback loop writes size_used_ elements. A crafted TESSDATA_INTTEMP component with version_id 4 or later can therefore set reserved to a small value and size_used_ to a large value when fontinfo_table_.read(fp, read_info) is called from src/classify/intproto.cpp, causing a heap out-of-bounds write of FontInfo structures, heap corruption, a crash, or potentially controlled corruption. No fixed release is available as of this review.
Title		Tesseract: Heap out-of-bounds write in GenericVector<T>::read due to independent reserved/size_used_ fields
Weaknesses		CWE-787
References		https://github.com/tesseract-ocr/tesseract/commit/56e09ca12e751623fe796ce1554ce704bffd2ef0 https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-88qp-4g94-3rf3
Metrics		cvssV4_0 `{'score': 8.6, 'vector': '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'}`