CVE-2025-70347
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn issue in mquickjs before commit 74b7e (2026-01-15) allows a local attacker to cause a denial of service via a crafted file to the get_mblock_size function at mquickjs.c.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceA denial of service vulnerability exists in the mquickjs JavaScript engine where a crafted file processed by the get_mblock_size function in mquick.c can trigger a crash or hang. The vulnerability is due to insufficient validation of file data affecting memory block size calculations.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify if mquickjs is in useSearch for mquickjs library files, executables, or dependencies in the environment (e.g., find / -name '*mquick*' 2>/dev/null or check package managers)Affected if mquickjs is found and used in the environment
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Determine the installed versionCheck the mquickjs version string via --version flag, library metadata, or source code version file. If using a git checkout, run 'git log -1 --format=%H' in the mquickjs directoryAffected if The version is older than commit 74b7e (January 15, 2026) or the version cannot be determined
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Verify file processing is enabledInspect the application or service configuration to confirm the mquickjs file processing feature is actively used (e.g., check for JS file loading, script compilation from files, or module loading from disk)Affected if The application processes JavaScript files or compiles scripts from file input using mquickjs
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Confirm the vulnerable code pathInspect the get_mblock_size function in mquick.c for the patch (look for added validation bounds checks around memory block size calculations). Compare the installed source to the post-fix commitAffected if The source code lacks the validation fixes present in commit 74b7e, or binary analysis shows no bounds checking in that function
The environment is affected if mquickjs is present, processes files, and the version predates the January 15, 2026 commit 74b7e fix.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedUpdate mquickjs to a version after commit 74b7e (January 15, 2026). If immediate patching is not possible, restrict processing of untrusted files and implement file size/content validation before passing files to mquickjs.
Upgrade to mquickjs version/commit 74b7e or later
- 1. Identify the current version of mquickjs in use by checking the source code or build artifacts
- 2. If using a version before commit 74b7e, obtain the version that includes commit 74b7e or later
- 3. Upgrade mquickjs to the version containing the fix for the get_mblock_size function vulnerability
- 4. Rebuild and redeploy any applications or systems using mquickjs
- 5. Test to verify the denial of service vulnerability is mitigated
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-70347 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-70347 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data