Interpreter crash via anchor-node double free
Published Jul 16, 2026 · Updated Jul 16, 2026
Use-after-free in bundled libsyck in Todd Rinaldo YAML::Syck before 1.47 allows attackers to crash Perl via a crafted YAML document. On anchor redefinition or removal, syck_hdlr_add_anchor and syck_hdlr_remove_anchor free a node that remains on the parser value stack, and syck_hdlr_add_node frees it again. The default Load and LoadFile paths require no special flags; any application parsing the seven-byte trigger from an untrusted source terminates its interpreter.
Summary
What happened
Use-after-free in bundled libsyck in Todd Rinaldo YAML::Syck before 1.47 allows attackers to crash Perl via a crafted YAML document. On anchor redefinition or removal, syck_hdlr_add_anchor and syck_hdlr_remove_anchor free a node that remains on the parser value stack, and syck_hdlr_add_node frees it again. The default Load and LoadFile paths require no special flags; any application parsing the seven-byte trigger from an untrusted source terminates its interpreter.
The record
- CVE
- CVE-2026-13713
- Published
- Jul 16, 2026
- Updated
- Jul 16, 2026
- Vendor
- Todd Rinaldo
- Product
- YAML::Syck
- Classifications
- CWE-415, CWE-416, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 16, 2026CVE publishedPublication date reported by the CVE source.
- Jul 16, 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 <1.47
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 anchor-node regression triggerproof of concept · validated
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Technologies
Your stack
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Your stack
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