CVE-2026-4177

Advisory lineage Upstream: 0 Downstream: 1
Awaiting Analysis
Published: 16 Mar 2026, 22:30
Last modified:17 Mar 2026, 14:04

Vulnerability Summary

Overall Risk (default)
high
70/100
CVSS Score
9.1 CRITICAL
v3.1 (cve.org)
EPSS Score
<0.01% LOW
0% probability
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

16 Mar 2026, 22:30
Published
Vulnerability first disclosed
17 Mar 2026, 14:04
Last Modified
Vulnerability information updated

Description

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 Metrics

  • v3.1•CRITICAL•Score: 9.1CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

EPSS Trends

Current EPSS score: 0.01%• Percentile: 0%

Techniques & Countermeasures

  • CWE-122•Heap-based Buffer Overflow

    A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

Affected Systems

  • toddr•yaml::syck

    ≤ 1.36

References (3)