Process crash via unbounded TOML parser recursion
Published Jul 24, 2026 · Updated Jul 24, 2026
Uncontrolled recursion in TOML::XS before 0.06 allows context-dependent attackers to crash a consuming process via deeply nested TOML. The bundled tomlc99 parser's parse_keyval and parse_array functions recursively descend dotted keys and nested arrays without limiting depth, exhausting the call stack. The service-interrupt impact requires an application to pass attacker-controlled TOML to from_toml; the affected process terminates with a stack-overflow fault.
Summary
What happened
Uncontrolled recursion in TOML::XS before 0.06 allows context-dependent attackers to crash a consuming process via deeply nested TOML. The bundled tomlc99 parser's parse_keyval and parse_array functions recursively descend dotted keys and nested arrays without limiting depth, exhausting the call stack. The service-interrupt impact requires an application to pass attacker-controlled TOML to from_toml; the affected process terminates with a stack-overflow fault.
The record
- CVE
- CVE-2026-16634
- Published
- Jul 24, 2026
- Updated
- Jul 24, 2026
- Vendor
- Felipe Gasper
- Product
- TOML::XS
- Classifications
- CWE-1395, CWE-1104, T1499.004
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Jul 24, 2026CVE publishedPublication date reported by the CVE source.
- Jul 24, 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 <0.06
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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
- tomlc99 deep-nesting stack-overflow proofs of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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