Denial of service via unreleased token buffers
Published Jun 29, 2026 · Updated Jun 29, 2026
Memory leak in JavaScript::Minifier::XS before 0.16 allows attackers to exhaust process memory through repeated minify() calls. In JsMinify in XS.xs, cleanup frees NodeSet structures but not each token buffer allocated by JsSetNodeContents, while JsDiscardNode unlinks nodes without freeing their contents. A long-lived process must invoke minify() repeatedly; memory then grows without bound until the process is killed, causing a service interruption.
Summary
What happened
Memory leak in JavaScript::Minifier::XS before 0.16 allows attackers to exhaust process memory through repeated minify() calls. In JsMinify in XS.xs, cleanup frees NodeSet structures but not each token buffer allocated by JsSetNodeContents, while JsDiscardNode unlinks nodes without freeing their contents. A long-lived process must invoke minify() repeatedly; memory then grows without bound until the process is killed, causing a service interruption.
The record
- CVE
- CVE-2026-56018
- Published
- Jun 29, 2026
- Updated
- Jun 29, 2026
- Vendor
- Graham TerMarsch
- Product
- JavaScript::Minifier::XS
- Classifications
- CWE-400, CWE-401, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 29, 2026CVE publishedPublication date reported by the CVE source.
- Jun 29, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <0.16
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Repeated-minify memory-growth test scriptproof of concept · unverified
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Technologies
Your stack
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Your stack
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