CPANSA-YAML-2019-25777: YAML vulnerability
| Publisher | giterlizzi | Document category | csaf_security_advisory |
|---|---|---|---|
| Initial release date | 2026-10-05T00:00:00 | Engine | CSAF Perl Toolkit 0.26 |
| Current release date | 2026-10-05T00:00:00 | Build Date | |
| Current version | 1 | Status | final |
| CVSS v3.1 Base Score | 7.3 | Severity | High |
| Original language | Language | en | |
| Also referred to | |||
Vulnerability Description
YAML versions before 1.27_001 for Perl allow a loaded perl/glob document to replace any package variable, which can lead to arbitrary code execution.
A perl/glob document names a package and a symbol, and supplies the value assigned to it. Nothing restricts the name, so the target can be @INC or YAML's own load options.
A perl/glob document that sets $YAML::LoadCode or $YAML::UseCode turns on code loading, which is off by default, for every later Load() in the process. A perl/code document is then passed to a string eval, so an attacker who supplies two documents to separate Load() calls in one process can execute arbitrary Perl code.
Vulnerabilities
CVE-2019-25777
Vulnerability DescriptionYAML versions before 1.27_001 for Perl allow a loaded perl/glob document to replace any package variable, which can lead to arbitrary code execution.
A perl/glob document names a package and a symbol, and supplies the value assigned to it. Nothing restricts the name, so the target can be @INC or YAML's own load options.
A perl/glob document that sets $YAML::LoadCode or $YAML::UseCode turns on code loading, which is off by default, for every later Load() in the process. A perl/code document is then passed to a string eval, so an attacker who supplies two documents to separate Load() calls in one process can execute arbitrary Perl code.
| Weakness | CWE-502 : Deserialization of Untrusted Data |
|---|
Product status
Known affected
| Product | Score | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| YAML less than 1.28 |
|
Fixed
- YAML greater than or equal 1.28
giterlizzi
Namespace: https://github.com/giterlizzi/
gdt@cpan.org
References
- CPANSA-YAML-2019-25777 JSON self
https://raw.githubusercontent.com/giterlizzi/perl-CPANSA-CSAF/develop/csaf/white/2026/cpansa-yaml-2019-25777.json - https://github.com/ingydotnet/yaml-pm/commit/bace96b5e6661d521c7c515c94a09e081c911fce.patch external
https://github.com/ingydotnet/yaml-pm/commit/bace96b5e6661d521c7c515c94a09e081c911fce.patch - https://github.com/ingydotnet/yaml-pm/issues/212 external
https://github.com/ingydotnet/yaml-pm/issues/212 - https://metacpan.org/release/TINITA/YAML-1.28/changes external
https://metacpan.org/release/TINITA/YAML-1.28/changes - http://www.openwall.com/lists/oss-security/2026/10/05/7 external
http://www.openwall.com/lists/oss-security/2026/10/05/7 - CVE-2019-25777 (NVD) external
https://nvd.nist.gov/vuln/detail/CVE-2019-25777
Revision history
| Version | Date of the revision | Summary of the revision |
|---|---|---|
| 1 | Mon Oct 5 00:00:00 2026 | First release |
Sharing rules
TLP:WHITE
For the TLP version see: https://www.first.org/tlp/