Bug 2559338 (CVE-2026-115389)

Summary: CVE-2026-115389 wasmtime: wasmtime: Denial of Service via untracked host memory allocation in Val API
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: low Docs Contact:
Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Wasmtime. The runtime does not adequately account for host memory allocations when converting guest values through the dynamically-typed Val application programming interface (API), bypassing configured resource consumption limits. A malicious WebAssembly guest can exploit this vulnerability by returning crafted values that consume far more host memory than tracked. This uncontrolled memory allocation can exhaust system resources, resulting in a Denial of Service (DoS).
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-10-22 20:44:36 UTC
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.