CVE-2026-56018
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 · uneditedJavaScript::Minifier::XS versions before 0.16 for Perl leak memory on every call to minify(), allowing unbounded memory growth. In JsMinify (XS.xs) the cleanup frees only the NodeSet structures and never the per-token contents buffers allocated in JsSetNodeContents; JsDiscardNode unlinks nodes without freeing their contents. Each token's contents buffer is therefore leaked on every call, and the two early returns taken when the node list is empty leak the whole NodeSet. A long-lived process that minifies repeatedly, such as an asset pipeline or a server-side minifier endpoint, grows in memory without bound until it exhausts available memory and is killed, causing denial of service.
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 · high confidenceJavaScript::Minifier::XS versions before 0.16 have a memory leak in the XS.xs cleanup code. The JsDiscardNode function frees NodeSet structures but fails to free per-token contents buffers allocated by JsSetNodeContents, and early returns leak the entire NodeSet. Each minify() call leaks memory, causing unbounded growth in long-lived processes.
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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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.
-
Find installed JavaScript::Minifier::XS versionRun `perl -MJavaScript::Minifier::XS -e 'print $JavaScript::Minifier::XS::VERSION'` or check via CPAN/your package managerAffected if The version displayed is less than 0.16 or no version is returned (module not found)
-
Verify Perl module is actually loadedSearch running processes for Perl using this module: `ps aux | grep perl` and check application code for `use JavaScript::Minifier::XS` or `require JavaScript::Minifier::XS`Affected if The module is loaded in any Perl process and the version from step 1 is below 0.16
-
Identify long-lived Perl processes using this moduleReview any persistent Perl processes (daemons, workers, CGI processes that persist) that call minify() functionAffected if Long-running processes exist that invoke minify() - memory will grow unbounded with each call
-
Check for memory growth patternsMonitor memory usage of Perl processes over time using `ps -o pid,rss,vsz,comm -p <pid>` or process monitoring toolsAffected if Memory continuously increases without stabilization during minify operations in versions before 0.16
You are affected if JavaScript::Minifier::XS version is below 0.16 AND your environment runs long-lived processes that call the minify() function.
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 · scopedUpgrade to JavaScript::Minifier::XS version 0.16 or later. For long-running processes, monitor memory usage and restart until the patched version can be deployed.
JavaScript::Minifier::XS version 0.16
- Check the currently installed version of JavaScript::Minifier::XS by running: perl -MJavaScript::Minifier::XS -e 'print $JavaScript::Minifier::XS::VERSION'
- Upgrade the module to version 0.16 or later using your Perl package manager (e.g., cpanm JavaScript::Minifier::[email protected] or cpan JavaScript::Minifier::XS)
- Verify the upgrade was successful by re-running the version check command from step 1
- If using in application code, re-run any test suites to confirm the memory leak is resolved
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-56018 — 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-2026-56018 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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