🛡️ CVE-2026-13713 on Ubuntu — libyaml-syck-perl

⚪ Unknown ✅ No Known Exploit OSV
N/A
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

YAML::Syck versions before 1.47 for Perl allow a use-after-free and double-free via an anchor node freed while still on the parser value stack. In the bundled libsyck, when an anchor name is redefined or removed, syck_hdlr_add_anchor and syck_hdlr_remove_anchor free the node stored under that name with syck_free_node. That node can still be live on the parser's value stack, so syck_hdlr_add_node reaches it again and frees it a second time. On a normal build the 48-byte node chunk is freed twice and the interpreter aborts. Anchors need no special flags, so this is reached on the default Load path, and a 7-byte document that redefines an anchor triggers it. Any caller that runs Load or LoadFile on an untrusted document that redefines an anchor mid-parse crashes the interpreter, a denial of service.

Distribution advisory

This page covers CVE-2026-13713 as tracked by Ubuntu, for the package libyaml-syck-perl. No fixed version has been recorded for this distribution yet.

How this vulnerability can be exploited

This issue can be reached with local access to the system, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Affected software

UBUNTU-CVE-2026-13713 is recorded against 1 package.

  • libyaml-syck-perl

Timeline and source

Published on 16 July 2026 and last revised on 29 July 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

ubuntu.com (Report)
www.cve.org (Report)
www.openwall.com (Report)
github.com (Report)
metacpan.org (Report)
www.openwall.com (Report)

Details

Severity Unknown
CVSS Score N/A
CVSS Vector CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2026-07-16
Updated 2026-08-11
Modified 2026-07-29
Fix URL N/A

Affected Packages

Software From version Fixed in
libyaml-syck-perl — —

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