CVE-2026-115389: Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not adequately account for host allocations when lifting guest values through the…

PriorityP413low2.3CVSS 3.1

AVAACHPRLUIRSUCNINAL

Wasmtime before 36.0.16, 37.0.0 before 48.0.3, and 49.0.0 before 49.0.1 does not adequately account for host allocations when lifting guest values through the dynamically-typed Val API, bypassing the hostcall fuel limit. A malicious WebAssembly guest can return crafted values that allocate at least ~100x more host memory than tracked, causing denial of service.

Affected

3 ranges

Vendor	Product	Version range	Fixed in
bytecodealliance	wasmtime	< 36.0.16	36.0.16
bytecodealliance	wasmtime	>= 37.0.0 < 48.0.3	48.0.3
bytecodealliance	wasmtime	>= 49.0.0 < 49.0.1	49.0.1

CVSS provenance

nvdv3.12.3LOWCVSS:3.1/AV:A/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:L

nvdv4.01.0LOWCVSS:4.0/AV:A/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/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

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