Service hang via exponential brace recursion
Published Jun 30, 2026 · Updated Jun 30, 2026
Denial of service in Julian Gruber brace-expansion 5.0.6 and earlier allows attackers to hang a calling process via crafted brace groups. The expand_ function recursively expands the remaining post string before early-return branches discard that work, doubling recursion for each non-expanding brace group. Exposure requires an application to pass attacker-influenced strings directly or transitively to expand(); one short input can block a Node.js event loop for minutes or indefinitely.
Summary
What happened
Denial of service in Julian Gruber brace-expansion 5.0.6 and earlier allows attackers to hang a calling process via crafted brace groups. The expand_ function recursively expands the remaining post string before early-return branches discard that work, doubling recursion for each non-expanding brace group. Exposure requires an application to pass attacker-influenced strings directly or transitively to expand(); one short input can block a Node.js event loop for minutes or indefinitely.
The record
- CVE
- CVE-2026-13149
- Published
- Jun 30, 2026
- Updated
- Jun 30, 2026
- Vendor
- Julian Gruber
- Product
- brace-expansion
- Classifications
- CWE-407, CWE-400, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 30, 2026CVE publishedPublication date reported by the CVE source.
- Jun 30, 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 <=5.0.6
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
- GHSA-3jxr-9vmj-r5cp proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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