CVE-2026-119339: Tesseract: Crafted LSTM model (`WeightMatrix` mode byte) triggers `ASSERT_HOST` abort in `WeightMatrix::DeSerializeOld` under `FAST_FLOAT` — Denial of Service

Q: Which deployments are most likely to be exposed?

Deployments using Tesseract versions before 5.5.4 that load traineddata LSTM networks are affected. Default FAST_FLOAT builds are specifically vulnerable because the malformed mode byte reaches an ASSERT_HOST abort.

Q: What must an attacker be able to do to trigger the denial of service?

An attacker needs to cause the application to load a crafted traineddata LSTM model through TessBaseAPI::Init. The issue is triggered by a malicious WeightMatrix mode byte in that model, rather than by OCR input alone.

Q: How can I determine whether my application is potentially affected?

It is potentially affected if it uses Tesseract earlier than 5.5.4, is built with FAST_FLOAT, and accepts or loads traineddata models from an untrusted source. A successful trigger terminates the process during model initialization.

Q: What is the available remediation?

Upgrade Tesseract to version 5.5.4, which fixes the issue. Until upgraded, avoid loading untrusted traineddata LSTM models.

Published Oct 30, 2026

Updated

Tesseract is an open source OCR engine. Prior to 5.5.4, WeightMatrix::DeSerialize trusts a mode byte from a traineddata LSTM network and calls WeightMatrix::DeSerializeOld when kDoubleFlag is clear. In default FASTFLOAT builds, DeSerializeOld invokes ASSERTHOST instead of returning an error, so loading a crafted model through TessBaseAPI::Init terminates the process and causes denial of service. This issue is fixed in version 5.5.4.

Affected Software

12 affected components

debian/tesseract<=5.3.0-2, <=5.5.0-1, <=5.5.0-1.1

debian/tesseract*

ubuntu/tesseract*

Event History

Oct 30, 2026

CVE Published

via MITRE·08:13 PM

Data Sourced

via MITRE·08:13 PM

DescriptionSeverityWeakness

Data Sourced

via NVD·09:16 PM

DescriptionSeverityWeakness

Data Sourced

via OSV·09:16 PM

Affected Software

Frequently Asked Questions

Which deployments are most likely to be exposed?

Deployments using Tesseract versions before 5.5.4 that load traineddata LSTM networks are affected. Default FAST_FLOAT builds are specifically vulnerable because the malformed mode byte reaches an ASSERT_HOST abort.

What must an attacker be able to do to trigger the denial of service?

An attacker needs to cause the application to load a crafted traineddata LSTM model through TessBaseAPI::Init. The issue is triggered by a malicious WeightMatrix mode byte in that model, rather than by OCR input alone.

How can I determine whether my application is potentially affected?

It is potentially affected if it uses Tesseract earlier than 5.5.4, is built with FAST_FLOAT, and accepts or loads traineddata models from an untrusted source. A successful trigger terminates the process during model initialization.

What is the available remediation?

Upgrade Tesseract to version 5.5.4, which fixes the issue. Until upgraded, avoid loading untrusted traineddata LSTM models.

CVE-2026-119339: Tesseract: Crafted LSTM model (`WeightMatrix` mode byte) triggers `ASSERT_HOST` abort in `WeightMatrix::DeSerializeOld` under `FAST_FLOAT` — Denial of Service

Affected Software

Event History

Frequently Asked Questions

Which deployments are most likely to be exposed?

What must an attacker be able to do to trigger the denial of service?

How can I determine whether my application is potentially affected?

What is the available remediation?

Company

Resources

Contact

Frequently Asked Questions

Which deployments are most likely to be exposed?

What must an attacker be able to do to trigger the denial of service?

How can I determine whether my application is potentially affected?

What is the available remediation?