What’s Vulnerable › Vulnerabilities

CVE-2026-115383: Wasmtime 47.0.0 before 48.0.4 and 49.0.0 before 49.0.2 GC Heap Corruption via Tag Imports

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-22 · updated 2026-10-22
• Weakness: CWE-1287

Description

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.

Affected products

• bytecodealliance wasmtime: from 47.0.0 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-cfhf-m2cr-62wj
• https://www.vulncheck.com/advisories/wasmtime-47.0.0-before-48.0.4-and-49.0.0-before-49.0.2-gc-heap-corruption-via-tag-imports

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