---
id: "CVE-2026-115385"
kind: "vulnerability"
aliases: ["CVE-2026-115385"]
title: "Wasmtime: guest timestamp calls crash the host process on Unix"
severity: "medium"
cvss: 6.9
epss: 0.00112
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["runtime", "self-hosted", "unix", "wasmtime", "webassembly"]
not_affected_if: ["default-config", "no-preopened-dirs", "trusted-guests-only"]
published_at: "2026-10-22T19:17:45+00:00"
first_seen_at: "2026-10-23T21:57:31+00:00"
updated_at: "2026-10-25T03:38:48+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-115385", "first_seen_at": "2026-10-23T21:57:31+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-115385", "first_seen_at": "2026-10-24T07:15:51+00:00"}]
---

# Wasmtime: guest timestamp calls crash the host process on Unix

Wasmtime's WASIp3 implementation in wasmtime-wasi asserts when a guest passes a negative (pre-epoch) seconds value to set-times or set-times-at. A guest with mutable preopened directory access can use this to abort the host process.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `wasmtime --version` and compare against the affected ranges: 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2.
- Check whether your application uses the wasmtime-wasi WASIp3 preview with mutable preopened directories.

## Fix

- Upgrade Wasmtime to `48.0.4` or `49.0.2` (or a later release in the same line).

## Timeline

- 2026-10-23T21:57:31+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-115385
- 2026-10-24T07:15:51+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-115385

## From the sources

Wasmtime 46.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a denial of service vulnerability in the wasmtime-wasi WASIp3 implementation that allows guests to abort the Unix host process. Guests with mutable preopened directory access can call set-times or set-times-at with negative seconds timestamps before the epoch, triggering an assertion failure that crashes the host.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_