Description
Wasmtime 47.0.0 before 48.0.6 and 49.0.0 before 49.0.3 contains a memory misalignment flaw in VMContext layout that causes undefined behavior when modules contain an odd number of exception tags. A WebAssembly module with an odd tag count misaligns subsequent host fields in embedders with exceptions enabled, although no exploitation path is currently known.
References2
Metrics
- CVSS 3.1
-
2.6
LOW
Score source: CNA
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:L/A:N - CVSS 4.0
-
2.1
LOW
Score source: CNA
CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 11 · as of 2 November 2026
- CWE
- CWE-758
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.