Bug 2559297 (CVE-2026-115386)

Summary: CVE-2026-115386 wasmtime: wasmtime: Information disclosure via uninitialized struct padding in fd_readdir
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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. An information disclosure vulnerability exists in the WebAssembly System Interface (WASI) directory reading implementation, which copies uninitialized structure padding into guest memory. A guest module with access to a preopened directory can exploit this issue by listing directory entries to read residual host stack or heap memory.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-10-22 20:18:58 UTC 
Wasmtime before 36.0.17, 37.0.0 before 48.0.4, and 49.0.0 before 49.0.2 contains an information disclosure vulnerability in the WASIp1 fd_readdir implementation that copies uninitialized struct padding into guest memory. Guests with a preopened directory can list entries to receive three bytes of leftover host stack or heap memory per directory entry.