Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains. Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth limit. It is possible to construct a name which saturates the call stack (at least with larger TCP responses), leading to a potential Denial of Service. The guard `$link < $offset` prevents forward and circular chains, but still allows arbitrarily long backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full depth. A crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data. The vulnerability is triggered by `Net::DNS::Packet->new(\$wire)` i.e. any point where the library decodes a DNS message from the network.

The remote Debian 11 / 12 host has a package installed that is affected by a vulnerability as referenced in the dla-4761 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-4761-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                       Guilhem Moulin     August 30, 2026                               https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : libnet-dns-perl     Version        : 1.29-1+deb11u1 1.36-1+deb12u1     CVE ID         : CVE-2026-64194     Debian Bug     : 1142503

    Steffen Ullrich discovered that libnet-dns-perl, a Perl module to     perform DNS queries, was vulnerable to Denial of Service via deep     RFC 1035 compression pointer chains.

    For Debian 11 bullseye, this problem has been fixed in version     1.29-1+deb11u1.

    For Debian 12 bookworm, this problem has been fixed in version     1.36-1+deb12u1.

    We recommend that you upgrade your libnet-dns-perl packages.

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

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS     Attachment:
    signature.asc     Description: PGP signature

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 remote Debian 13 host has a package installed that is affected by multiple vulnerabilities as referenced in the dsa-6459 advisory.

    - -------------------------------------------------------------------------     Debian Security Advisory DSA-6459-1                   security@debian.org     https://www.debian.org/security/                     Salvatore Bonaccorso     August 22, 2026                       https://www.debian.org/security/faq
    - -------------------------------------------------------------------------

    Package        : libnet-dns-perl     CVE ID         : CVE-2026-64193 CVE-2026-64194     Debian Bug     : 1142503

    Two vulnerabilities were discovered in libnet-dns-perl, a Perl module to     perform DNS queries, which could result in denial of service or remote     code execution.

    For the stable distribution (trixie), these problems have been fixed in     version 1.56-0+deb13u1.

    We recommend that you upgrade your libnet-dns-perl packages.

    For the detailed security status of libnet-dns-perl please refer to its     security tracker page at:
    https://security-tracker.debian.org/tracker/libnet-dns-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 these issues but has instead relied only on the application's self-reported version number.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-2046 advisory.

    Net::DNS versions through 1.55 for Perl allow remote execution injection via EDNS EXTENDED ERROR.

    Net::DNS::RR::OPT::EXTENDED_ERROR::_decompose parses the EXTRA-TEXT field of an EDNS EXTENDED-ERROR option     (RFC 8914) by tokenising the raw bytes and passing the result to Perl's eval. There is some escaping done     for $ and @, but not for backticks. This can be exploited for command execution if     $pkt->edns->option('EXTENDED-ERROR') is called in array context, for example with a payload of     {0:`<command>`} in EXTRA-TEXT. (CVE-2026-64193)

    Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains.

    Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth     limit. It is possible to construct a name which saturates the call stack (at least with larger TCP     responses), leading to a potential Denial of Service.

    The guard `$link < $offset` prevents forward and circular chains, but still allows arbitrarily long     backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits     only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full     depth.

    A crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than     the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383)     this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field     (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process     receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data.

    The vulnerability is triggered by `Net::DNS::Packet->new(\$wire)` i.e. any point where the library decodes     a DNS message from the network. (CVE-2026-64194)

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

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

The version of perl-Net-DNS installed on the remote host is prior to 0.72-6. It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3855 advisory.

    Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains.

    Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth     limit. It is possible to construct a name which saturates the call stack (at least with larger TCP     responses), leading to a potential Denial of Service.

    The guard `$link < $offset` prevents forward and circular chains, but still allows arbitrarily long     backward chains. The per-offset cache (`$cache`) is populated at the start of each call and short-circuits     only re-traverses of the same offset - the initial descent through a fresh chain still recurses at full     depth.

    A crafted packet can chain two-byte compression pointers so that each one points two bytes earlier than     the previous, producing a chain length of `offset / 2`. For the 14-bit pointer field (max offset 16383)     this gives up to ~8191 recursive frames. For a TCP DNS message the limit is the 16-bit length field     (~32767 frames). Perl's default C stack handles only a few thousand frames; beyond that the process     receives SIGSEGV or similar, which is a denial-of-service for any application parsing untrusted DNS data.

    The vulnerability is triggered by `Net::DNS::Packet->new(\$wire)` i.e. any point where the library decodes     a DNS message from the network. (CVE-2026-64194)

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 SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has a package installed that is affected by a vulnerability as referenced in the SUSE-SU-2026:3456-1 advisory.

    This update for perl-Net-DNS fixes the following issue

    - CVE-2026-64194: RFC 1035 compression pointers are followed via recursion with no depth limit     established, which       can lead to DoS when specially crafted DNS packets are parsed (bsc#1272214).

Tenable has extracted the preceding description block directly from the SUSE 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 SUSE Linux SLES12 host has a package installed that is affected by a vulnerability as referenced in the SUSE- SU-2026:3431-1 advisory.

    This update for perl-Net-DNS fixes the following issue

    - CVE-2026-64194: RFC 1035 compression pointers are followed via recursion with no depth limit     established, which       can lead to DoS when specially crafted DNS packets are parsed (bsc#1272214).

Tenable has extracted the preceding description block directly from the SUSE 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 openSUSE 16 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:21437-1 advisory.

    Changes in perl-Net-DNS:

    - CVE-2026-64194: Fixed a Denial of Service via deep DNS compression pointer chains [bsc#1272214]
    - CVE-2026-64193: Fixed a remote execution injection [bsc#1272212]

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

Note that Nessus has not tested for these issues 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.

  - Net::DNS versions through 1.55 for Perl allow Denial of Service via deep DNS compression pointer chains.
    Net::DNS::DomainName::decode follows RFC 1035 compression pointers by recursing into itself with no depth     limit. It is possible to construct a name which saturates the call stack (at least with larger TCP     responses), leading to a potential Denial of Service. The guard `$link < $offset` prevents forward and     circular chains, but still allows arbitrarily long backward chains. The per-offset cache (`$cache`) is     populated at the start of each call and short-circuits only re-traverses of the same offset - the initial     descent through a fresh chain still recurses at full depth. A crafted packet can chain two-byte     compression pointers so that each one points two bytes earlier than the previous, producing a chain length     of `offset / 2`. For the 14-bit pointer field (max offset 16383) this gives up to ~8191 recursive frames.
    For a TCP DNS message the limit is the 16-bit length field (~32767 frames). Perl's default C stack handles     only a few thousand frames; beyond that the process receives SIGSEGV or similar, which is a denial-of-     service for any application parsing untrusted DNS data. The vulnerability is triggered by     `Net::DNS::Packet->new(\$wire)` i.e. any point where the library decodes a DNS message from the network.
    (CVE-2026-64194)

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

ID	Name	Product	Family	Type	Severity
341610	Debian dla-4761 : libnet-dns-perl - security update	Nessus	Debian Local Security Checks	Local	high
338856	Debian dsa-6459 : libnet-dns-perl - security update	Nessus	Debian Local Security Checks	Local	critical
337214	Amazon Linux 2023 : perl-Net-DNS, perl-Net-DNS-Nameserver, perl-Net-DNS-tests (ALAS2023-2026-2046)	Nessus	Amazon Linux Local Security Checks	Local	critical
337206	Amazon Linux 2 : perl-Net-DNS, --advisory ALAS2-2026-3855 (ALAS-2026-3855)	Nessus	Amazon Linux Local Security Checks	Local	high
331848	SUSE SLED15 / SLES15 Security Update : perl-Net-DNS (SUSE-SU-2026:3456-1)	Nessus	SuSE Local Security Checks	Local	high
331548	SUSE SLES12 Security Update : perl-Net-DNS (SUSE-SU-2026:3431-1)	Nessus	SuSE Local Security Checks	Local	high
329516	openSUSE 16 Security Update : perl-Net-DNS (openSUSE-SU-2026:21437-1)	Nessus	SuSE Local Security Checks	Local	critical
328335	Linux Distros Unpatched Vulnerability : CVE-2026-64194	Nessus	Misc.	Local	high

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CVE-2026-64194

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