CVE-2026-8257
WebAssembly Binaryen BrOn wasm-ir-builder.cpp makeBrOn assertion
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.
INFO
Published Date :
May 11, 2026, 2:16 a.m.
Last Modified :
May 21, 2026, 5:59 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | LOW | [email protected] | ||||
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | LOW | [email protected] |
Solution
- Install the patch to address the BrOn Parser issue.
- Update WebAssembly Binaryen to the latest version.
- Review and apply the provided patch identifier.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-8257.
| URL | Resource |
|---|---|
| https://github.com/HackC0der/CVE-Repos/blob/main/wasm-binaryen/Assertion_Failure_isRef_wasm_Type_getHeapType_commit_3ef8d19 | Exploit |
| https://github.com/WebAssembly/binaryen/ | Product |
| https://github.com/WebAssembly/binaryen/commit/1251efbc1ea471c1311d2726b2bbe061ff2a291c | Patch |
| https://github.com/WebAssembly/binaryen/issues/8633 | Exploit Issue Tracking Third Party Advisory |
| https://github.com/WebAssembly/binaryen/pull/8635 | Mitigation Patch |
| https://vuldb.com/submit/809552 | Third Party Advisory VDB Entry |
| https://vuldb.com/vuln/362554 | Third Party Advisory VDB Entry |
| https://vuldb.com/vuln/362554/cti | Permissions Required VDB Entry |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-8257 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-8257
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-8257 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-8257 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 21, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:webassembly:binaryen:*:*:*:*:*:*:*:* versions up to (including) 117 Added Reference Type VulDB: https://github.com/HackC0der/CVE-Repos/blob/main/wasm-binaryen/Assertion_Failure_isRef_wasm_Type_getHeapType_commit_3ef8d19 Types: Exploit Added Reference Type VulDB: https://github.com/WebAssembly/binaryen/ Types: Product Added Reference Type VulDB: https://github.com/WebAssembly/binaryen/commit/1251efbc1ea471c1311d2726b2bbe061ff2a291c Types: Patch Added Reference Type VulDB: https://github.com/WebAssembly/binaryen/issues/8633 Types: Exploit, Issue Tracking, Third Party Advisory Added Reference Type VulDB: https://github.com/WebAssembly/binaryen/pull/8635 Types: Mitigation, Patch Added Reference Type VulDB: https://vuldb.com/submit/809552 Types: Third Party Advisory, VDB Entry Added Reference Type VulDB: https://vuldb.com/vuln/362554 Types: Third Party Advisory, VDB Entry Added Reference Type VulDB: https://vuldb.com/vuln/362554/cti Types: Permissions Required, VDB Entry -
New CVE Received by [email protected]
May. 11, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 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 Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L Added CVSS V2 (AV:L/AC:L/Au:S/C:N/I:N/A:P) Added CWE CWE-617 Added Reference https://github.com/HackC0der/CVE-Repos/blob/main/wasm-binaryen/Assertion_Failure_isRef_wasm_Type_getHeapType_commit_3ef8d19 Added Reference https://github.com/WebAssembly/binaryen/ Added Reference https://github.com/WebAssembly/binaryen/commit/1251efbc1ea471c1311d2726b2bbe061ff2a291c Added Reference https://github.com/WebAssembly/binaryen/issues/8633 Added Reference https://github.com/WebAssembly/binaryen/pull/8635 Added Reference https://vuldb.com/submit/809552 Added Reference https://vuldb.com/vuln/362554 Added Reference https://vuldb.com/vuln/362554/cti