Remote service crash via unbounded schema recursion
Published Jul 27, 2026 · Updated Jul 27, 2026
Uncontrolled recursion in llama.cpp e15efe0 allows remote attackers to crash an exposed server through a crafted response_format schema. The transform() routine in common/json-schema-to-grammar.cpp recursively descends each nested regex group without enforcing a depth limit, exhausting the process stack. Reachability requires a deployment that accepts attacker-controlled JSON schemas through llama-server; successful input terminates the process but does not read or modify data.
Summary
What happened
Uncontrolled recursion in llama.cpp e15efe0 allows remote attackers to crash an exposed server through a crafted response_format schema. The transform() routine in common/json-schema-to-grammar.cpp recursively descends each nested regex group without enforcing a depth limit, exhausting the process stack. Reachability requires a deployment that accepts attacker-controlled JSON schemas through llama-server; successful input terminates the process but does not read or modify data.
The record
- CVE
- CVE-2026-17501
- Published
- Jul 27, 2026
- Updated
- Jul 27, 2026
- Vendor
- Georgi Gerganov
- Product
- llama.cpp
- Classifications
- CWE-674, CWE-404, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 27, 2026CVE publishedPublication date reported by the CVE source.
- Jul 27, 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?
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- Affected versionversion=e15efe0
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
- Deep group nesting schema reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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