Application crash via unbounded recursive data traversal
Published Mar 3, 2026 · Updated Mar 3, 2026
Uncontrolled recursion in Underscore.js before 1.13.8 allows remote attackers to crash applications through deeply nested input. The _.flatten and _.isEqual implementations recursively traverse attacker-shaped arrays or objects without a depth limit, causing an uncaught stack overflow. Exploitation requires application code to pass unbounded untrusted structures into these functions under the advisory's function-specific conditions; the bounded consequence is a restartable application crash.
Summary
What happened
Uncontrolled recursion in Underscore.js before 1.13.8 allows remote attackers to crash applications through deeply nested input. The _.flatten and _.isEqual implementations recursively traverse attacker-shaped arrays or objects without a depth limit, causing an uncaught stack overflow. Exploitation requires application code to pass unbounded untrusted structures into these functions under the advisory's function-specific conditions; the bounded consequence is a restartable application crash.
The record
- CVE
- CVE-2026-27601
- Published
- Mar 3, 2026
- Updated
- Mar 3, 2026
- Vendor
- Jeremy Ashkenas
- Product
- Underscore.js
- Classifications
- CWE-770, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 3, 2026CVE publishedPublication date reported by the CVE source.
- Mar 3, 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=< 1.13.8
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
- Upstream deeply nested input proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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