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CVE-2026-4177 affects YAML::Syck for Perl through version 1.36 and covers multiple memory-safety flaws, the most severe of which is a heap-based buffer overflow in the YAML emitter. The overflow occurs when class names exceed the emitter’s initial 512-byte allocation, leading to writes beyond the allocated heap buffer during emission. Additional issues associated with the same CVE include an out-of-bounds read in the base64 decoder when processing trailing newlines, in-place mutation of n->type_id by strtok that can corrupt shared node data, and a memory leak in syck_hdlr_add_anchor when a node already has an anchor and the incoming anchor string is discarded on early return. The vulnerability set affects the YAML::Syck distribution’s handling of YAML data and memory management, with the heap overflow representing the primary security concern.
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9 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
A heap buffer overflow vulnerability in the YAML emitter.
A vulnerability in YAML::Syck through version 1.36 for Perl involving multiple security issues, including a high-severity heap buffer overflow in the YAML emitter, out-of-bounds read in the base64 decoder, shared node data corruption, and a memory leak.
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Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.