# Guest can panic host through filesystem timestamp before the epoch on wasip3

Advisory record · `GHSA-mr2v-56j5-cmfc`

- **Identifiers:** `GHSA-mr2v-56j5-cmfc` · `CVE-2026-115385` · `RUSTSEC-2026-0324`
- **State:** Confirmed
- **Severity:** CVSS 6.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-754](https://cwe.mitre.org/data/definitions/754.html)
- **Tags:** [CWE-754](https://agentprime.io/advisories/tag/cwe-754.md)
- **Published:** 2 Oct 2026
- **Updated:** 24 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 2 Oct 2026, 12:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `wasmtime-wasi` (crates.io): affected `>=46.0.0, <48.0.4 || >=49.0.0, <49.0.2`; fixed in `48.0.4`, `49.0.2`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Wasmtime-wasi versions 46.0.0 to before 48.0.4, and 49.0.0 to before 49.0.2, are affected. A guest module running on wasip3 can cause the host to panic through a filesystem timestamp set before the epoch; the source gives few further details on conditions or impact. Upgrade to wasmtime-wasi 48.0.4 or 49.0.2.

Written 3 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 6.9 Medium, CVSS 4.0: `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`, from CNA (VulnCheck)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0011, the 1st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:24 UTC: First seen by agentprime
- 31 Oct 2026, 14:24 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/RUSTSEC-2026-0324)

## Sources

- [GitHub Advisory Database: GHSA-mr2v-56j5-cmfc](https://github.com/advisories/GHSA-mr2v-56j5-cmfc)
- [OSV: GHSA-mr2v-56j5-cmfc](https://osv.dev/vulnerability/GHSA-mr2v-56j5-cmfc)
- <https://crates.io/crates/wasmtime-wasi>
- <https://rustsec.org/advisories/RUSTSEC-2026-0324.html>
- <https://github.com/bytecodealliance/wasmtime/pull/14486>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-mr2v-56j5-cmfc>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-mr2v-56j5-cmfc/>. Everything for agents: <https://agentprime.io/llms.txt>.