Vulnerability in Bytecodealliance Wasmtime
CVE-2026-115383
Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 contains an improper validation vulnerability that accepts components whose core modules import WebAssembly tags with a subtype of the original type. Malicious guests can mis-type exception object payloads to corrupt the GC heap, causing Wasmtime to panic when the exceptions proposal is enabled.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/bytecodealliance/wasmtime/security/advisories/GHSA-cfhf-m2cr-62wj (vendor-advisory)
- www.vulncheck.com/advisories/wasmtime-47.0.0-before-48.0.4-and-49.0.0-before-49… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-115383?
- CVE-2026-115383 is a medium-severity vulnerability in Bytecodealliance Wasmtime, classified under CWE-1287. CVSS score: 4.8/10. Published 2026-10-22.
- How severe is CVE-2026-115383?
- Medium severity. CVSS v3 base score is 4.8 out of 10.