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CVE-2026-13713 CPAN Security Group
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CVE ID: CVE-2026-13713
Distribution: YAML-Syck
Versions: before 1.47
MetaCPAN: https://metacpan.org/dist/YAML-Syck
VCS Repo: https://github.com/toddr/YAML-Syck
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
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.
Problem types
-------------
- CWE-416 Use After Free
- CWE-415 Double Free
Solutions
---------
Upgrade to YAML-Syck 1.47 or later.
References
----------
https://metacpan.org/release/TODDR/YAML-Syck-1.47/changes
https://github.com/toddr/YAML-Syck/commit/44c90a109ec3215ee7ce747bd11209835e123d8b.patch
--
Paul Johnson - [email protected]
