# llama.cpp update adds guard against tensor size overflow

> The Sep 30 release prevents a rare overflow bug when padding large tensors, improving stability across platforms.

Oossa · 2026-09-30 · https://oossa.com/en/llama-cpp-update-adds-guard-against-tensor-size-overflow

The llama.cpp library released a patch on Sep 30, 2026, that blocks tensors whose size would overflow during padding. The change checks the raw size plus alignment before adding padding, rejecting unsafe tensors early. A new test case shows the fix catches a 2⁶⁴‑16‑byte tensor that previously slipped through. The update applies to all supported builds, from macOS to Windows and Linux, including CUDA and Vulkan versions.

## The facts

- Fix targets overflow when nbytes + (alignment‑1) exceeds SIZE_MAX
- Test case uses tensor dimensions [4, 2³⁰‑1, 2³⁰+1, 1]

## Why it matters

Stopping this overflow prevents crashes or corrupted results when running very large models.

## Sources & references

1. [ggml-org/llama.cpp b11275](https://github.com/ggml-org/llama.cpp/releases/tag/b11275) – llama.cpp, 2026-09-30
2. [ggml-org/llama.cpp b11276](https://github.com/ggml-org/llama.cpp/releases/tag/b11276) – llama.cpp, 2026-09-30

Last updated: 2026-09-30