CVE-2026-4177
libyaml-syck-perl - security update
9.1
CRITICAL
CVSS 3.1
EPSS 0.02%
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.
How to fix CVE-2026-4177
To remediate CVE-2026-4177, upgrade the affected package to a fixed version below.
- —upgrade to 1.45-r0 or later
- —upgrade to 1.34-1+deb11u1 or later
- —upgrade to 1.34-2+deb12u2 or later
Is CVE-2026-4177 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (3)
- from 0, < 1.45-r0
- from 0, < 1.34-1+deb11u1
- from 0, < 1.34-2+deb12u2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |