# CVE-2026-116816: llama.cpp b5899 before b10261 Heap Out-of-Bounds Write via plamo2 Tokenizer


- **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
- **Fix available:** Yes
- **Published:** 27 Oct 2026
- **Updated:** 27 Oct 2026
- **Also known as:** DEBIAN-CVE-2026-116816, GHSA-3r8c-j789-2864, UBUNTU-CVE-2026-116816

## What is CVE-2026-116816?

CVE-2026-116816 is a high-severity vulnerability in ggml-org llama.cpp, published on 27 Oct 2026. 

### Official description

llama.cpp b5899 before b10261 contains a heap out-of-bounds write vulnerability in llm_tokenizer_plamo2::build that allows attackers to corrupt heap memory via crafted GGUF models. Attackers can supply BYTE-typed token text like <0x-1> whose negative parsed value writes token ids before the bytes_ buffer during model loading, causing crashes or potential code execution.

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2026-116816?


## How do I fix CVE-2026-116816?

Upgrade to a fixed version.

## Is CVE-2026-116816 being exploited?

There is no known exploitation of CVE-2026-116816 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-116816 and fix it if it is affected.

What it is: CVE-2026-116816 is a high-severity vulnerability in ggml-org llama.cpp, published on 27 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-116816 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-2026-116816/ (Markdown: https://insights.sbomify.com/CVE-2026-116816/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-116816
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-116816
- OSV: https://osv.dev/vulnerability/CVE-2026-116816

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-116816/
Summaries are generated and may contain mistakes; the official description above is the record.