# CVE-2026-88048: Tesseract: Heap out-of-bounds write/read in FullyConnected::Forward via layer/weight-matrix dimension mismatch

> A crafted traineddata file can trigger heap out-of-bounds write and read in Tesseract's LSTM engine, potentially leading to code execution or crashes.

- **Severity:** High 8.6 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Sep 2026
- **Updated:** 11 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-88048, ECHO-18ac-cecc-73b2, GHSA-q44c-23p6-5mw6, UBUNTU-CVE-2026-88048

## What is CVE-2026-88048?

CVE-2026-88048 is a high-severity memory corruption vulnerability in tesseract-ocr tesseract, published on 10 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

Tesseract is an open source OCR engine. In version 5.5.3 and earlier, FullyConnected::DeSerialize in src/lstm/fullyconnected.cpp does not validate the deserialized layer scalars ni_ and no_ against the weight-matrix dimensions. During FullyConnected::Forward, MatrixDotVector in src/lstm/weightmatrix.cpp writes w.dim1() results into temp_line, which is sized from no_, and reads w.dim2() minus one inputs from curr_input, which is sized from ni_. A crafted .traineddata NT_SOFTMAX layer can therefore use inconsistent dimensions to cause a heap out-of-bounds write and read on the default LSTM engine, resulting in heap corruption, a crash, information disclosure, or potentially controlled corruption. No fixed release is available as of this review.

Weakness: CWE-787 (Out-of-bounds Write), CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-88048?

It affects 1 product.


Products: Tesseract-Ocr Tesseract Ocr.

## How do I fix CVE-2026-88048?

No fix published yet.

## Is CVE-2026-88048 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-88048 exists.

## Other vulnerabilities in tesseract-ocr tesseract

- [CVE-2026-88047](https://insights.sbomify.com/CVE-2026-88047/): Tesseract: ReadNormProtos stack buffer overflow (high 8.6)
- [CVE-2026-88049](https://insights.sbomify.com/CVE-2026-88049/): Tesseract: Heap out-of-bounds write in LSTM::Forward via na_/gate-matrix dimension mismatch (high 8.6)
- [CVE-2026-88051](https://insights.sbomify.com/CVE-2026-88051/): Tesseract: Heap out-of-bounds write in GenericVector<T>::read due to independent reserved/size_used_ fields (high 8.6)
- [CVE-2026-88053](https://insights.sbomify.com/CVE-2026-88053/): Tesseract: Heap out-of-bounds write in Classify::ReadIntTemplates via unvalidated counts in crafted .traineddata (high 8.6)
- [CVE-2026-88052](https://insights.sbomify.com/CVE-2026-88052/): Tesseract: Heap out-of-bounds write in UNICHARSET::load_via_fgets via count/insert desynchronization (high 7.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-88048 and fix it if it is affected.

What it is: CVE-2026-88048 is a high-severity memory corruption vulnerability in tesseract-ocr tesseract, published on 10 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-88048 exists.

Affected product: tesseract-ocr tesseract. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-88048/ (Markdown: https://insights.sbomify.com/CVE-2026-88048/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-88048
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-88048
- OSV: https://osv.dev/vulnerability/CVE-2026-88048

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-88048/
Summaries are generated and may contain mistakes; the official description above is the record.