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CVE-2026-8257
WebAssembly Binaryen BrOn wasm-ir-builder.cpp makeBrOn assertion
Medium4.8EPSS 0.16%
- Published
- Updated
- Reserved
- Assigned by
- VulDB
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulDBCNA (assigner) | 4.0 | Medium4.8 | CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P |
| VulDBCNA (assigner) | 3.1 | Low3.3 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C |
| VulDBCNA (assigner) | 3.0 | Low3.3 | CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C |
| VulDBCNA (assigner) | 2.0 | Low1.7 | AV:L/AC:L/Au:S/C:N/I:N/A:P/E:POC/RL:OF/RC:C |
| NVDNVD · Analyzed | 4.0 | Low1.9 | CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.16% · top 95% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 4.8.
Weakness
Affected products
- affected 117
References (8)
- VDB-362554 | WebAssembly Binaryen BrOn wasm-ir-builder.cpp makeBrOn assertion (opens in a new tab)vdb-entrytechnical-description
- VDB-362554 | CTI Indicators (IOB, IOC, IOA) (opens in a new tab)signaturepermissions-required
- 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) (opens in a new tab)third-party-advisory
- https://github.com/WebAssembly/binaryen/issues/8633 (opens in a new tab)issue-tracking
- https://github.com/WebAssembly/binaryen/pull/8635 (opens in a new tab)issue-trackingpatch
- https://github.com/HackC0der/CVE-Repos/blob/main/wasm-binaryen/Assertion_Failure_isRef_wasm_Type_getHeapType_commit_3ef8d19 (opens in a new tab)exploitpatch
- https://github.com/WebAssembly/binaryen/commit/1251efbc1ea471c1311d2726b2bbe061ff2a291c (opens in a new tab)patch
- https://github.com/WebAssembly/binaryen/ (opens in a new tab)product
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-8257)Record last updated .