CVE-2026-4177
Published: March 17, 2026Last modified: March 28, 2026
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 9.1 |
| Attack Vector | NETWORK |
| Attack complexity | LOW |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | NONE |
| Availability impact | HIGH |
| Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | perl-yaml-syck | Fixed (1.34-r3) |
| 25 LTS | perl-yaml-syck | Fixed (1.34-r6) | |
| Stream | perl-yaml-syck | Fixed (1.37-r0) |
References
- 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://github.com/cpan-authors/YAML-Syck/commit/e8844a31c8cf0052914b198fc784ed4e6b8ae69e.patch
- https://metacpan.org/release/TODDR/YAML-Syck-1.37_01/changes#L21
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-4177.json