Bug 2562040

Summary: CVE-2026-115889 tree-sitter: Wasmtime: Bit-packing in Cranelift compiler causes silent overflow and miscompilation [fedora-all]
Product: [Fedora] Fedora Reporter: Ronit Dey <rdey>
Component: tree-sitterAssignee: Andreas Schneider <asn>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: rawhideCC: asn, mavit, michel, suraj.ghimire7
Target Milestone: ---Keywords: Security, SecurityTracking
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Hardware: Unspecified   
OS: Unspecified   
Whiteboard: {"flaws": ["1f7b86f7-6147-424f-a05b-da56033b46af"]}
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On:    
Bug Blocks: 2560221    

Description Ronit Dey 2026-10-27 15:09:00 UTC 
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

Wasmtime is a runtime for WebAssembly. Prior to 36.0.19 and 43.0.0, the Cranelift compiler backend bit-packs SSA value indices in a way that can silently overflow in release builds when compiling a sufficiently large or specially crafted Wasm function with many SSA values. The overflow can make Cranelift reference incorrect IR values, causing arbitrary miscompilation, type confusion, and other attacker-controlled effects that may escape the Wasm sandbox on any architecture using the default Cranelift backend. This issue is fixed in versions 36.0.19 and 43.0.0.