CVE-2026-8257 PUBLISHED

A vulnerability was detected in WebAssembly Binaryen up to 117. This issue affects the function IRBuilder::makeBrOn of the file src/wasm/wasm-ir-builder.cpp of the component BrOn Parser. Performing a manipulation results in reachable assertion. The attack needs to be approached locally. The exploit is now public and may be used. The patch is named 1251efbc1ea471c1311d2726b2bbe061ff2a291c. It is suggested to install a patch to address this issue.

• pwn3rd (VulDB User) reporter

• VDB-362554 | WebAssembly Binaryen BrOn wasm-ir-builder.cpp makeBrOn assertion
• VDB-362554 | CTI Indicators (IOB, IOC, IOA)
• Submit #809552 | WebAssembly Community Binaryen main branch commit 3ef8d19 (v117 development version, vulnerable version before fix commit 1251efb) Fixed version: commit 1251ef Assertion Failure, Denial of Service (Local DoS)
• https://github.com/WebAssembly/binaryen/issues/8633
• https://github.com/WebAssembly/binaryen/pull/8635
• https://github.com/HackC0der/CVE-Repos/blob/main/wasm-binaryen/Assertion_Failure_isRef_wasm_Type_getHeapType_commit_3ef8d19
• https://github.com/WebAssembly/binaryen/commit/1251efbc1ea471c1311d2726b2bbe061ff2a291c
• https://github.com/WebAssembly/binaryen/

• Reachable Assertion CWE