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. 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->type_id in place, corrupting shared node data. A memory leak occurred in syck_hdlr_add_anchor when a node already had an anchor. The incoming anchor string 'a' was leaked on early return.

CVSS v3 9.1 CRITICAL

9.1^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.2

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/cpan-authors/YAML-Syck/commit/e8844a31c8cf0052914b198fc784ed4e6b8ae69e.patch	Patch
https://metacpan.org/release/TODDR/YAML-Syck-1.37_01/changes#L21	Release Notes
http://www.openwall.com/lists/oss-security/2026/03/16/6	Mailing List Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:toddr:yaml\:\:syck:*:*:*:*:*:perl:*:*

History

No history.

Information

Published : 2026-03-16 23:16

Updated : 2026-03-23 18:17

NVD link : CVE-2026-4177

Mitre link : CVE-2026-4177

CVE.ORG link : CVE-2026-4177

JSON object : View

Products Affected

toddr

yaml\

CWE

CWE-122

Heap-based Buffer Overflow

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