What’s Vulnerable › Vulnerabilities

CVE-2026-115384: Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 Stack Buffer Overflow

• Severity: critical (CVSS 9.9 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-22 · updated 2026-10-29
• Weakness: CWE-20

Description

Wasmtime 39.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains a stack buffer overflow vulnerability that allows malicious guests to write ~16KB to the native stack via unvalidated async callback result types. Attackers can supply components with mistyped component-model-async callback functions to overwrite return addresses, crashing the host or escaping the sandbox.

Affected products

• bytecodealliance wasmtime: from 39.0.0 before 48.0.4; from 49.0.0 before 49.0.2 — fixed in 48.0.4, 49.0.2

How to fix

Upgrade to a fixed version: bytecodealliance wasmtime 48.0.4, 49.0.2. Check the vendor advisory for mitigations.

References

• https://github.com/bytecodealliance/wasmtime/security/advisories/GHSA-32h6-97mm-8q3c
• https://www.vulncheck.com/advisories/wasmtime-39.0.0-before-48.0.4-and-49.0.0-before-49.0.2-stack-buffer-overflow

Get alerted when CVE-2026-115384 or the next vulnerability affects your stack