CVE-2026-8257: A vulnerability was detected in WebAssembly Binaryen up to 117

Q: How do I fix CVE-2026-8257?

binaryen: upgrade to newer than 117. Exact commands for each OS are on this page.

Q: Is CVE-2026-8257 being exploited?

CVE-2026-8257 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-8257 affect?

CVE-2026-8257 affects binaryen. Severity is low (CVSS 3.3). 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 assert

Q: How urgent is CVE-2026-8257?

Priority 18/100. Public exploit reference

Routine

LOW 3.3UPGRADE

CVE-2026-8257 is a low-severity flaw (CVSS 3.3) affecting binaryen. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	3.3 (Low)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 95%)
CISA exploited list	No
Weakness	CWE-617
Published	2026-05-11
Last modified	2026-07-23

Publisher (CNA): VulDB · Vendor: webassembly

Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-11 02:16 UTCPublished CVE record published
2026-07-23 20:10 UTCUpdated Record last modified

webassembly binaryen UPGRADE

Affected: <= 117

Fixed in: newer than 117

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy binaryen || rpm -q binaryen || binaryen --version

2. UPGRADE to newer than 117 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade binaryen

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade binaryen

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-8257?

binaryen: upgrade to newer than 117. Exact commands for each OS are on this page.

Is CVE-2026-8257 being exploited?

CVE-2026-8257 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-8257 affect?

CVE-2026-8257 affects binaryen. Severity is low (CVSS 3.3). 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 assert

How urgent is CVE-2026-8257?

Priority 18/100. Public exploit reference

References

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