GHSA-32h6-97mm-8q3c: wasmtime (CVE-2026-115384)

Wasmtime component async-lifted callback result count is unvalidated, causing a native stack buffer overflow

CVSS 9.4 CriticalCriticalEPSS 0.0031 · 24th percentile

Critical, because:

CVSS score 9.4: 9.0 or more.

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.

Package	Ecosystem	Affected	Fixed in
wasmtime	crates.io	>=39.0.0, <48.0.4 \|\| >=49.0.0, <49.0.2	48.0.4, 49.0.2

Identifiers

GHSA-32h6-97mm-8q3c · CVE-2026-115384 · RUSTSEC-2026-0327

Weakness (CWE)

CWE-20

Machine-written summary

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

Wasmtime versions from 39.0.0 before 48.0.4, and from 49.0.0 before 49.0.2, are affected by a native stack buffer overflow in component async-lifted callback handling, where the callback result count is not validated. The source gives few details on what triggers it or what access an attacker needs. Upgrade to Wasmtime 48.0.4 or 49.0.2, depending on your release line.

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

Score	Rating	CVSS	Vector	Source
9.4	Critical	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0031, the 24th percentile, on 7 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

Sources

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.