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CVE-2026-27204

MEDIUM CVSS 4.0: 6.9 EPSS 0.08%
Updated Feb 25, 2026
Bytecodealliance
Parameter Value
CVSS 6.9 (MEDIUM)
Affected Versions 25.0.0 — 41.0.4
Fixed In 24.0.6
Type CWE-789, CWE-774, CWE-400 (Uncontrolled Resource Consumption), CWE-770 (Allocation Without Limits)
Vendor Bytecodealliance
Public PoC No

Wasmtime is a runtime for WebAssembly. Prior to versions 24.0.6, 36.0.6, 4.0.04, 41.0.4, and 42.0.0, Wasmtime's implementation of WASI host interfaces are susceptible to guest-controlled resource exhaustion on the host. Wasmtime did not appropriately place limits on resource allocations requested by the guests.

This serves as a Denial of Service vector. Wasmtime 24.0.6, 36.0.6, 40.0.4, 41.0.4, and 42.0.0 have all been released with the fix for this issue. These versions do not prevent this issue in their default configuration to avoid breaking preexisting behaviors.

All versions of Wasmtime have appropriate knobs to prevent this behavior, and Wasmtime 42.0.0-and-later will have these knobs tuned by default to prevent this issue from happening. There are no known workarounds for this issue without upgrading. Embedders are recommended to upgrade and configure their embeddings as necessary to prevent possibly-malicious guests from triggering this issue.

Attack Parameters

Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
Present
Additional conditions required
Privileges Required
Low
Basic privileges needed
User Interaction
Passive
Minimal interaction

Impact Assessment

Confidentiality
None
No data leak
Integrity
None
No data modification
Availability
High
Complete denial of service

CVSS Vector v4.0

Vulnerable Products 4

Configuration From (including) Up to (excluding)
Bytecodealliance Wasmtime
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*
24.0.6
Bytecodealliance Wasmtime
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*
25.0.0 36.0.6
Bytecodealliance Wasmtime
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*
37.0.0 40.0.4
Bytecodealliance Wasmtime
cpe:2.3:a:bytecodealliance:wasmtime:*:*:*:*:*:rust:*:*
41.0.0 41.0.4