CVE-2026-4177: YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high-severity heap buffer overflow in the YAML emitter
YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities including a high-severity heap buffer overflow in the YAML emitter.
The heap overflow occurs when class names exceed the initial 512-byte allocation.
The base64 decoder could read past the buffer end on trailing newlines.
strtok mutated n->typeid in place, corrupting shared node data.
A memory leak occurred in syckhdlraddanchor when a node already had an anchor. The incoming anchor string 'a' was leaked on early return.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
YAML::Syck (Perl)to a version that resolves this vulnerability.Fixed in 1.37 - Compensating control
If upgrading is not immediately possible, limit exposure by processing YAML::Syck inputs only from trusted sources and avoid parsing untrusted YAML on affected systems until the upgrade to 1.37 or higher is completed.
Event History
Frequently Asked Questions
What is the severity of CVE-2026-4177?
CVE-2026-4177 is considered to have a high severity due to a heap buffer overflow vulnerability.
How do I fix CVE-2026-4177?
To mitigate CVE-2026-4177, upgrade to YAML::Syck version 1.37 or later.
What components are affected by CVE-2026-4177?
CVE-2026-4177 affects YAML::Syck versions up to and including 1.36 for Perl.
What kind of vulnerability is described in CVE-2026-4177?
CVE-2026-4177 describes a heap buffer overflow vulnerability within the YAML emitter.
Who is responsible for YAML::Syck and CVE-2026-4177?
CVE-2026-4177 is associated with the development of the YAML::Syck Perl module.