What’s Vulnerable › Vulnerabilities

CVE-2026-8257: WebAssembly Binaryen BrOn wasm-ir-builder.cpp makeBrOn assertion

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-11 · updated 2026-07-23
• Weakness: CWE-617

Description

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.

Affected products

• WebAssembly Binaryen: through 117

References

• https://github.com/HackC0der/CVE-Repos/blob/main/wasm-binaryen/Assertion_Failure_isRef_wasm_Type_getHeapType_commit_3ef8d19
• https://github.com/WebAssembly/binaryen/
• https://github.com/WebAssembly/binaryen/commit/1251efbc1ea471c1311d2726b2bbe061ff2a291c
• https://github.com/WebAssembly/binaryen/issues/8633
• https://github.com/WebAssembly/binaryen/pull/8635
• https://vuldb.com/submit/809552
• https://vuldb.com/vuln/362554
• https://vuldb.com/vuln/362554/cti

Get alerted when CVE-2026-8257 or the next vulnerability affects your stack