CVE-2026-88054

Tesseract: Denial of service via empty-stack dereference in Plumbing/Series at model load

Published Sep 10, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed

Description

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, Plumbing::DeSerialize in src/lstm/plumbing.cpp rejects excessively large network stacks but accepts a zero-length stack for NT_SERIES, NT_PARALLEL, or NT_REVERSED layers in a crafted .traineddata model. During LSTMRecognizer initialization in src/lstm/lstmrecognizer.cpp, CacheXScaleFactor(XScaleFactor()) reaches Series::CacheXScaleFactor in src/lstm/series.cpp, which dereferences stack_[0] on the empty vector and invokes a virtual method through an invalid Network pointer. This causes a deterministic crash and denial of service at model load. No fixed release is available as of this review.

Analysis

Technical impact

A defensive check in Tesseract is bypassed when a malicious arithmetic model file contains a zero-length stack for NT_SERIES, NT_PARALLEL, or NT_REVERSED layers. The code reaches CacheXScaleFactor and dereferences stack_[0] on an empty vector, invoking an invalid virtual method through a malformed Network object. This deterministic crash occurs during LSTMRecognizer initialization, resulting in a denial of service when the model is loaded. The weakness is an out-of-bounds read and a misuse of object lifetime, reflected in CWE-125 and CWE-824.

Affected Systems

The vulnerability affects the tesseract-ocr tesseract engine version 5.5.3 and all earlier releases. Any deployment relying on these versions to load traineddata models is susceptible.

Risk and Exploitability

The CVSS score of 6.9 classifies the vulnerability as moderate, though the EPSS score is unavailable, so the exploitation likelihood cannot be precisely quantified. The vulnerability is not listed in the CISA KEV catalog, indicating no known active exploitation. Attackers would need to supply a crafted .traineddata file to the model loader, either locally or through a remote-facing interface that accepts model uploads. The deterministic nature of the crash makes detection straightforward, but the impact can be significant if mission-critical systems rely on continuous OCR processing.

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

Upgrade to any Tesseract release newer than 5.5.3 once a patch is available, as future versions will eliminate the empty-stack dereference.
Validate that all .traineddata files originate from trusted sources before loading them; reject or quarantine any model from unverified origins.
Apply a custom code patch that checks for an empty stack in Plumbing::DeSerialize or Series::CacheXScaleFactor before dereferencing, or disable the LSTM recognizer for processes that must remain stable until the official fix is released.

Generated by OpenCVE AI on September 10, 2026 at 23:46 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 None

Vulnerable System Integrity Impact None

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 None

Integrity Impact None

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% (0.153% probability within 30 days)

Exploitation poc

Automatable no

Technical Impact partial

References

Link	Providers
https://github.com/tesseract-ocr/tesseract/commit/552771236b0d80cbdb0c7dd856120fa21a4672e5
https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-f6h7-cqr4-6fx4
https://nvd.nist.gov/vuln/detail/CVE-2026-88054
https://www.cve.org/CVERecord?id=CVE-2026-88054

History

Sep 16, 2026 4:30 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': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'}`	cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}`

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-2026-88054 https://www.cve.org/CVERecord?id=CVE-2026-88054
Metrics	threat_severity `None`	cvssV3_1 `{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'}` threat_severity `Moderate`

Sep 10, 2026 7:30 PM Scoring metrics updated View changes

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

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, Plumbing::DeSerialize in src/lstm/plumbing.cpp rejects excessively large network stacks but accepts a zero-length stack for NT_SERIES, NT_PARALLEL, or NT_REVERSED layers in a crafted .traineddata model. During LSTMRecognizer initialization in src/lstm/lstmrecognizer.cpp, CacheXScaleFactor(XScaleFactor()) reaches Series::CacheXScaleFactor in src/lstm/series.cpp, which dereferences stack_[0] on the empty vector and invokes a virtual method through an invalid Network pointer. This causes a deterministic crash and denial of service at model load. No fixed release is available as of this review.
Title		Tesseract: Denial of service via empty-stack dereference in Plumbing/Series at model load
Weaknesses		CWE-125 CWE-824
References		https://github.com/tesseract-ocr/tesseract/commit/552771236b0d80cbdb0c7dd856120fa21a4672e5 https://github.com/tesseract-ocr/tesseract/security/advisories/GHSA-f6h7-cqr4-6fx4
Metrics		cvssV4_0 `{'score': 6.9, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}`