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.
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History

Thu, 05 Nov 2026 17:45:00 +0000

Type Values Removed Values Added
Description 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.
Title WAMR fast interpreter loader heap buffer overflow via constant deduplication mismatch
Weaknesses CWE-787
References
Metrics cvssV4_0

{'score': 8.8, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:H/VA:H/SC:N/SI:N/SA:N'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-11-05T18:44:51.857Z

Reserved: 2026-06-16T13:49:33.556Z

Link: CVE-2026-54912

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-05T18:17:08.523

Modified: 2026-11-05T18:17:08.523

Link: CVE-2026-54912

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses