# CVE-2026-54912: WAMR fast interpreter loader heap buffer overflow via constant deduplication mismatch

Status: published. Published: 2026-11-05. Updated: 2026-11-05.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- bytecodealliance / wasm-micro-runtime: < 2.4.5 (affected). Source: CNA: GitHub_M

## Severity and prioritization

- CVSS 4.0: 8.8 (high); 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; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation poc; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-787

## Exploit evidence

- exploit: https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-jjv3-x3jf-cg49 (ADP: CISA-ADP)

## References

- https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-jjv3-x3jf-cg49 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/wasm-micro-runtime/wasm-micro-runtime/commit/b1353b5e8983047ff68829c99abf1355d5f389cf (CNA: GitHub_M; x_refsource_MISC)

- https://gist.github.com/shumbo/b710c35b005ed871447fce385d1ab760 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/wasm-micro-runtime/wasm-micro-runtime/releases/tag/WAMR-2.4.5 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/wasm-micro-runtime/wasm-micro-runtime/security/advisories/GHSA-jjv3-x3jf-cg49 (ADP: CISA-ADP; exploit)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-54912; retrieved 2026-11-05; source updated 2026-11-05

Revision: 297fbbf87271f176bf07ad6e4d914b8f8c1d8dec59b00220c43c43a08f4853f5

Canonical: https://y2.dev/cve/CVE-2026-54912

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