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.

The remote MiracleLinux 8 host has a package installed that is affected by a vulnerability as referenced in the AXSA:2026-405:01 advisory.

    * perl-YAML-Syck: YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities     including a high-severity heap buffer overflow in the YAML emitter (CVE-2026-4177)

Tenable has extracted the preceding description block directly from the MiracleLinux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote AlmaLinux 8 host has a package installed that is affected by a vulnerability as referenced in the ALSA-2026:6470 advisory.

    * perl-YAML-Syck: YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities     including a high-severity heap buffer overflow in the YAML emitter (CVE-2026-4177)

Tenable has extracted the preceding description block directly from the AlmaLinux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Oracle Linux 8 host has a package installed that is affected by a vulnerability as referenced in the ELSA-2026-6470 advisory.

    [1.30-6]
    - Resolves: RHEL-156475
    - Fix CVE-2026-4177

Tenable has extracted the preceding description block directly from the Oracle Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Redhat Enterprise Linux 8 host has a package installed that is affected by a vulnerability as referenced in the RHSA-2026:6470 advisory.

    This module provides a Perl interface to the libsyck data serialization library. It exports the Dump and     Load functions for converting Perl data structures to YAML strings, and the other way around.

    Security Fix(es):

    * perl-YAML-Syck: YAML::Syck versions through 1.36 for Perl has several potential security vulnerabilities     including a high-severity heap buffer overflow in the YAML emitter (CVE-2026-4177)

    For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and     other related information, refer to the CVE page(s) listed in the References section.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2026-1517 advisory.

    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. (CVE-2026-4177)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The version of perl-YAML-Syck installed on the remote host is prior to 1.27-3. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3216 advisory.

    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. (CVE-2026-4177)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Fedora 42 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2026-d226775800 advisory.

    `YAML::Syck` versions up to and including 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.


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Fedora 43 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2026-3572f7e01c advisory.

    `YAML::Syck` versions up to and including 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.


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Fedora 44 host has a package installed that is affected by a vulnerability as referenced in the FEDORA-2026-a8d89d8ae2 advisory.

    `YAML::Syck` versions up to and including 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.


Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The remote Debian 12 / 13 host has a package installed that is affected by a vulnerability as referenced in the dsa-6175 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6175-1                   security@debian.org     https://www.debian.org/security/                     Salvatore Bonaccorso     March 22, 2026                        https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : libyaml-syck-perl     CVE ID         : CVE-2026-4177

    Several vulnerabilities were discovered in libyaml-syck-perl, a Perl     module providing a fast, lightweight YAML loader and dumper, which may     result in denial of service and potentially arbitrary code execution.

    For the oldstable distribution (bookworm), this problem has been fixed     in version 1.34-2+deb12u2.

    For the stable distribution (trixie), this problem has been fixed in     version 1.34-2+deb13u2.

    We recommend that you upgrade your libyaml-syck-perl packages.

    For the detailed security status of libyaml-syck-perl please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/libyaml-syck-perl

    Further information about Debian Security Advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://www.debian.org/security/

    Mailing list: debian-security-announce@lists.debian.org

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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. (CVE-2026-4177)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Severity
305052	MiracleLinux 8 : perl-YAML-Syck-1.30-6.el8_10 (AXSA:2026-405:01)	Nessus	Miracle Linux Local Security Checks	critical
304953	AlmaLinux 8 : perl-YAML-Syck (ALSA-2026:6470)	Nessus	Alma Linux Local Security Checks	critical
304940	Oracle Linux 8 : perl-YAML-Syck (ELSA-2026-6470)	Nessus	Oracle Linux Local Security Checks	critical
304731	RHEL 8 : perl-YAML-Syck (RHSA-2026:6470)	Nessus	Red Hat Local Security Checks	critical
304616	Amazon Linux 2023 : perl-YAML-Syck, perl-YAML-Syck-tests (ALAS2023-2026-1517)	Nessus	Amazon Linux Local Security Checks	critical
304600	Amazon Linux 2 : perl-YAML-Syck, --advisory ALAS2-2026-3216 (ALAS-2026-3216)	Nessus	Amazon Linux Local Security Checks	critical
304388	Fedora 42 : perl-YAML-Syck (2026-d226775800)	Nessus	Fedora Local Security Checks	critical
304385	Fedora 43 : perl-YAML-Syck (2026-3572f7e01c)	Nessus	Fedora Local Security Checks	critical
304355	Fedora 44 : perl-YAML-Syck (2026-a8d89d8ae2)	Nessus	Fedora Local Security Checks	critical
303308	Debian dsa-6175 : libyaml-syck-perl - security update	Nessus	Debian Local Security Checks	critical
302536	Linux Distros Unpatched Vulnerability : CVE-2026-4177	Nessus	Misc.	critical

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