CVE-2026-4177
critical · 9.1YAML::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.
9.1
CVSS
0.4%
EPSS (exploit prob.)
37th
EPSS percentile
2026-03-16
Published
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Weaknesses
CWE-122CWE-120
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| toddr | yaml::syck | < 1.37 |
Check a specific version with /api/v1/cve/match.
References
- https://github.com/cpan-authors/YAML-Syck/commit/e8844a31c8cf0052914b198fc784ed4e6b8ae69e.patch
- https://metacpan.org/release/TODDR/YAML-Syck-1.37_01/changes#L21
- http://www.openwall.com/lists/oss-security/2026/03/16/6
- https://access.redhat.com/errata/RHSA-2026:6470
- https://access.redhat.com/errata/RHSA-2026:8311
- https://access.redhat.com/security/cve/CVE-2026-4177
- https://bugzilla.redhat.com/show_bug.cgi?id=2448277
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4177.json
Query this programmatically:
curl https://evil-db.io/api/v1/cve/CVE-2026-4177