Compilation interruption via exponential selector expansion
Published Jul 4, 2026 · Updated Jul 4, 2026
Resource-consumption flaw in Connor Skees grass 0.13.0 through 0.13.4 allows local users to interrupt compilation with crafted SCSS. The selector extension visitor recursively materializes a cross-product of nested parent and sibling combinators, consuming gigabytes of memory and substantial CPU for a tiny input. Exploitation requires a workflow that compiles attacker-controlled SCSS; the compiler eventually returns, and the maintainer disputes that expected exponential Sass behavior constitutes a security flaw.
Summary
What happened
Resource-consumption flaw in Connor Skees grass 0.13.0 through 0.13.4 allows local users to interrupt compilation with crafted SCSS. The selector extension visitor recursively materializes a cross-product of nested parent and sibling combinators, consuming gigabytes of memory and substantial CPU for a tiny input. Exploitation requires a workflow that compiles attacker-controlled SCSS; the compiler eventually returns, and the maintainer disputes that expected exponential Sass behavior constitutes a security flaw.
The record
- CVE
- CVE-2026-14651
- Published
- Jul 4, 2026
- Updated
- Jul 4, 2026
- Vendor
- Connor Skees
- Product
- grass
- Classifications
- CWE-404, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 4, 2026CVE publishedPublication date reported by the CVE source.
- Jul 4, 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=0.13.0
- Affected versionversion=0.13.1
- Affected versionversion=0.13.2
- Affected versionversion=0.13.3
- Affected versionversion=0.13.4
What conditions does exploitation require?
What is affected?
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
- GitHub issue 117 SCSS reproducerproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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