# CVE-2026-70638: llama.cpp b1886–b7445 Integer Overflow via new_1batch() in llama-android.cpp

> Integer overflow in llama.cpp Android JNI wrapper allows attackers to cause heap corruption and execute arbitrary code via crafted model files.

- **Severity:** High 8.5 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/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:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 6 Aug 2026
- **Updated:** 29 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-70638, GHSA-p56f-gv6x-v6mg

## What is CVE-2026-70638?

CVE-2026-70638 is a high-severity vulnerability in ggml-org llama.cpp, published on 6 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

llama.cpp builds b1886 through b7445 contain an integer overflow vulnerability in the LLaMA-Android JNI wrapper where the new_1batch() function multiplies sizeof(llama_seq_id) by an attacker-controlled n_seq_max parameter without overflow validation, causing heap buffer allocation to wrap and allocate insufficient memory. Attackers can exploit this by providing a crafted n_seq_max value through a malicious model file or JNI call to trigger heap corruption and achieve denial of service or arbitrary code execution on Android applications using the LLaMA-Android binding.

Weakness: CWE-190 (Integer Overflow or Wraparound), CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2026-70638?

It affects 1 product.


Products: Ggml Llama.cpp.

## How do I fix CVE-2026-70638?

Apply the vendor's patch.

## Is CVE-2026-70638 being exploited?

There is no known exploitation of CVE-2026-70638 in the wild and no public exploit code.

Public exploit code:

- https://github.com/Hunt-Benito/one-multiply-too-many-cve-2026-70638-llama-cpp-android-jni-integer-overflow (github_poc): https://github.com/Hunt-Benito/one-multiply-too-many-cve-2026-70638-llama-cpp-android-jni-integer-overflow

## Other vulnerabilities in ggml-org llama.cpp

- [CVE-2024-42479](https://insights.sbomify.com/CVE-2024-42479/): llama.cpp allows write-what-where in rpc_server::set_tensor (critical 10.0)
- [CVE-2026-34159](https://insights.sbomify.com/CVE-2026-34159/): llama.cpp: Unauthenticated RCE via GRAPH_COMPUTE buffer=0 bypass in llama.cpp RPC backend (critical 9.8)
- [CVE-2026-43629](https://insights.sbomify.com/CVE-2026-43629/): llama.cpp b4882–b9058 Buffer Overflow in KV Cache State Restore (critical 9.2)
- [CVE-2026-43631](https://insights.sbomify.com/CVE-2026-43631/): llama.cpp b7492–b9060 Use-After-Free RCE via llama-server (critical 9.2)
- [CVE-2026-43632](https://insights.sbomify.com/CVE-2026-43632/): llama.cpp b7492–b9060 Use-After-Free in Tokenization Endpoints (critical 9.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-70638 and fix it if it is affected.

What it is: CVE-2026-70638 is a high-severity vulnerability in ggml-org llama.cpp, published on 6 Aug 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-70638 in the wild and no public exploit code.

Affected product: ggml-org llama.cpp. 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-2026-70638/ (Markdown: https://insights.sbomify.com/CVE-2026-70638/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-70638
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-70638
- OSV: https://osv.dev/vulnerability/CVE-2026-70638

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-70638/
Summaries are generated and may contain mistakes; the official description above is the record.