Host application crash via unbounded builtin recursion
Published Dec 16, 2025 · Updated Dec 16, 2025
Denial of service in expr-lang Expr before 1.17.7 allows remote attackers to crash host applications via crafted evaluation data. The flatten, min, max, mean, and median builtins recursively traverse nested or cyclic arrays without a depth limit, exhausting the Go runtime stack instead of returning an evaluation error. Reachability requires an application to evaluate attacker-influenced environments containing pathological depth or cycles; controlled, acyclic data does not trigger the crash.
Summary
What happened
Denial of service in expr-lang Expr before 1.17.7 allows remote attackers to crash host applications via crafted evaluation data. The flatten, min, max, mean, and median builtins recursively traverse nested or cyclic arrays without a depth limit, exhausting the Go runtime stack instead of returning an evaluation error. Reachability requires an application to evaluate attacker-influenced environments containing pathological depth or cycles; controlled, acyclic data does not trigger the crash.
The record
- CVE
- CVE-2025-68156
- Published
- Dec 16, 2025
- Updated
- Dec 16, 2025
- Vendor
- expr-lang
- Product
- Expr
- Classifications
- CWE-770, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Dec 16, 2025CVE publishedPublication date reported by the CVE source.
- Dec 16, 2025Record 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=< 1.17.7
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
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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