CVE-2026-54912

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CVE-2026-54912

Summary: WAMR fast interpreter loader heap buffer overflow via constant deduplication mismatch

Details: WebAssembly Micro Runtime (WAMR) is a lightweight standalone WebAssembly (Wasm) runtime. Prior to 2.4.5, the two-pass fast interpreter loader in core/iwasm/interpreter/wasm_loader.c can make inconsistent constant-table decisions between the sizing pass and the emitting pass. After duplicate constants inflate the first pass beyond the constant-slot limit, wasm_loader_get_const_offset emits later constants inline, but the between-pass sort and deduplication reduces the table so the second pass can choose table references and cause reserve_block_ret to emit additional copy operands that were not included in code_compiled_peak_size. A crafted module can therefore make the second pass write partially attacker-controlled compiled-code data beyond the heap buffer allocated from the first pass's size calculation during wasm_runtime_load, before guest code executes. This can corrupt host heap metadata and deterministically crash the process, causing denial of service; further consequences depend on the host application's heap layout. Builds using WAMR_BUILD_FAST_INTERP=1 are affected; disabling the fast interpreter avoids the vulnerable loader. This issue is fixed in version 2.4.5.

References: https://gist.github.com/shumbo/b710c35b005ed871447fce385d1ab760, https://github.com/wasm-micro-runtime/wasm-micro-runtime/releases/tag/WAMR-2.4.5, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54912.json, https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-jjv3-x3jf-cg49, https://nvd.nist.gov/vuln/detail/CVE-2026-54912, https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/b1353b5e8983047ff68829c99abf1355d5f389cf