There are packages installed that are affected by multiple vulnerabilities referenced in the following CVEs:

  - In NLnet Labs Unbound 1.4.22 up to and including 1.25.1, UDP source port is randomized and intended to
    serve as a secret value that increases the entropy of DNS transactions. When resolver load balancing
    policies depend on the source port while their outcome is revealed this secrecy is undermined. The
    vulnerability arises when the load balancing policy is consistent with respect to the incoming source UDP
    port and IP address while heavily depending on the incoming source UDP port as a randomization source.
    When the SO_REUSEPORT configuration option is enabled ('so-reuseport: yes') in Unbound (by default), it
    meets these conditions, making it vulnerable for DNS cache poisoning attacks. Upon startup, Unbound
    randomly partitions the available UDP source port space into disjoint subsets of (almost) equal size,
    assigning each subset to a specific worker thread. When an incoming DNS query is received, the kernel’s
    SO_REUSEPORT load balancing mechanism deterministically assigns the query to a socket associated with a
    particular thread. All outgoing DNS queries generated during the resolution of that request use source
    ports selected exclusively from the port subset assigned to the corresponding thread. Since these port
    subsets are disjoint across threads, the source port observed in a resolver’s outgoing query to an
    authoritative name server serves as a reliable indicator of the worker thread that processed the original
    client query. A malicious actor can acquire the mapping between incoming UDP source ports (for a given
    fixed source IP address) and Unbound worker threads and leverage it to conduct DNS cache poisoning attacks
    by effectively lowering the random port population per thread. (CVE-2026-50252)

  - In NLnet Labs Unbound 1.16.2 up to and including 1.25.1, a similar vulnerability as with CVE-2026-40622 in
    the 'ghost domain names' family of attacks was found in Unbound that could extend the ghost domain window
    by up to one cached TTL configured value for A/AAAA glue records. Similar to other 'ghost domain names'
    attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single
    client A/AAAA query can cause Unbound to overwrite the cached expired parent-side glue rrset and
    essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In
    configurations where 'harden-referral-path: yes' is used (non-default configuration), no client query is
    required since Unbound implicitly performs that query. This is a variant of CVE-2026-40622 which only
    addressed the NS query. (CVE-2026-42955)

  - With NLnet Labs Unbound up to and including version 1.25.1, applications using libunbound and configured
    with 'unwanted-reply-threshold', could eventually be abruptly terminated if the threshold is reached and
    libunbound needs to call 'libworker_alloc_cleanup' since the function is absent from the function call
    allow list. When an application using libunbound sets 'unwanted-reply-threshold' to any non-zero value and
    the iterator queries an authoritative that replies with enough wrong-transaction-ID UDP datagrams to cross
    the threshold, the 'libworker_alloc_cleanup' will eventually be called. Since the function is absent from
    the function call allow list, this leads to a fatal exit of libunbound and eventual termination of the
    embedding application.Unbound itself is not affected since its relevant function 'worker_alloc_cleanup' is
    registed in the allow list and proceeds to perform the documented cache flush. (CVE-2026-44621)

  - In NLnet Labs Unbound 1.13.2 up to and including 1.25.1, stub or forward zones where the name is below an
    intermediate labed below a DNSSEC signed zone could be shadowed by the intermediate label's secure
    NXDOMAIN answer from the parent. This is caused by an off-by-one error in 'harden-below-nxdomain' logic;
    enabled by default. It effectively bypasses the configuration and the configured stub/forward zone is
    never contacted. 'harden-below-nxdomain' does an upward DNS cache walk together with a delegation point
    guard that does not allow NXDOMAIN synthesis above stub/forward zones. The guard tests the domain name but
    before stripping a label. This results in an iteration where the domain name equals the configured
    stub/forward zone apex that passes the guard, strips one more label, and probes the cache at the apex's
    immediate public parent. If that parent has a cached DNSSEC-secure NXDOMAIN, which it will for any private
    namespace nested two or more labels under a signed public name, the walk returns it and the configured
    stub/forward upstream is never contacted. This can only be triggered by the query for the intermediate
    label (between the stub/forward apex and the DNSSEC parent zone). (CVE-2026-44687)

  - In NLnet Labs Unbound 1.7.0 up to and including 1.25.1, insufficient validation of the RRSIG.Labels field
    combined with premature cache writes during RFC 8198 aggressive NSEC processing leads to cache poisoning
    that permits a malicious actor controlling a single delegated zone to poison arbitrary sibling zones under
    NSEC-signed parent domains. A malicious actor with one registered domain under an NSEC-signed TLD can
    serve malicious insecure DNS responses for unrelated sibling domains (sharing the same parent zone).
    Arbitrary delegations that do not exist under the parent domain and are covered by the parent's NSEC chain
    can be brought into insecure existence by fraudulent wildcard DS records (less labels than expected,
    unknown algorithm) from the malicious sibling domain. This allows the malicious actor to inject insecure
    wildcard records for those delegations. (CVE-2026-44690)

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

  - In NLnet Labs Unbound 1.16.2 up to and including 1.25.1, a similar vulnerability as with CVE-2026-40622 in     the 'ghost domain names' family of attacks was found in Unbound that could extend the ghost domain window     by up to one cached TTL configured value for A/AAAA glue records. Similar to other 'ghost domain names'     attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single     client A/AAAA query can cause Unbound to overwrite the cached expired parent-side glue rrset and     essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In     configurations where 'harden-referral-path: yes' is used (non-default configuration), no client query is     required since Unbound implicitly performs that query. This is a variant of CVE-2026-40622 which only     addressed the NS query. (CVE-2026-42955)

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

The version of FreeBSD installed on the remote host is prior to tested version. It is, therefore, affected by multiple vulnerabilities as referenced in the f63b4b88-6901-4c12-b13d-5a821e25e9bf advisory.

    NLnet Labs reports:
    This release consolidates security fixes for issues reported                 over a period of time. There are fixes for:

Tenable has extracted the preceding description block directly from the FreeBSD 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 remote Fedora 44 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-e495bd59ef advisory.

    Update to 1.25.2 (rhbz#2506061)

    Security fixes:

    - Fix CVE-2026-14586, Assertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC     environments. Thanks to Kunta Chu, Kaihua Wang, and Jianjun Chen from Tsinghua University, for the report.
    - Fix CVE-2026-32665, Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass. Thanks to     N0zoM1z0 (https://github.com/N0zoM1z0) for the report. In addition, thanks to Kunta Chu, Kaihua Wang, and     Jianjun Chen from Tsinghua University, for also reporting this issue. In addition, thanks to Qifan Zhang,     Palo Alto Networks, for also reporting this issue. In addition, thanks to Xuanchao Xie, for also reporting     this issue.
    - Fix CVE-2026-40691, Packet of death for DNSCrypt over TCP. Thanks to Qifan Zhang, Palo Alto Networks,     for the report. In addition, thanks to Trung Nguyen (@everping) of CyStack, for also reporting this issue.
    - Fix CVE-2026-41637, Degradation of resolution service from improperly accounted client-terminated DNS-     over-QUIC queries. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-42955, Extra fix for CVE-2026-40622 to also clamp the TTL of A/AAAA records disallowing a     one-time 'ghost domain' delegation renewal via glue records. Thanks to Qifan Zhang, Palo Alto Networks,     for the report.
    - Fix CVE-2026-44621, Libunbound applications configured with 'unwanted-reply-threshold' could eventually     be abruptly terminated. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-44687, Off-by-one error in 'harden-below-nxdomain' logic can shadow a stub/forward zone by     a legitimate parent's NXDOMAIN. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-44690, Cross-zone wildcard cache poisoning via RRSIG.labels manipulation. Thanks to Qifan     Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-46582, A wildcard replay, as another piece of data, triggers poisoning in the serve expired     reply path. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50045, 'max-global-quota' reset by DNSSEC validation restarts. Thanks to Kunjie Shang,     University of Science and Technology of China, for the report.
    - Fix CVE-2026-50046, Possible heap use-after-free in an error path when a DoT forwarded query is jostled     out. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50243, 'response-ip'/'rpz' can rewrite BOGUS answers instead of returning SERVFAIL. Thanks     to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50248, BOGUS configured primary hostname accepted for XFR in auth/rpz zones. Thanks to     Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50251, Attacker supplied `0.0.0.0`/`::` glue triggers defensive full-cache flush. Thanks to     Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50252, Possible cache poisoning attack by mapping source port population per thread. Thanks     to Inbal Schussheim and Amit Klein, Hebrew University, for the report.
    - Fix CVE-2026-52863, Memory corruption could lead to crash and denial of service. Thanks to Qifan Zhang,     Palo Alto Networks, for the report.
    - Fix CVE-2026-54478, DNS Cookie bypass when combined with proxy-protocol use. Thanks to Qifan Zhang, Palo     Alto Networks, for the report.
    - Fix CVE-2026-55708, Privacy/configuration issue when adding local data in views through 'unbound-     control'. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-55717, 'serve-expired-client-timeout' and 'response-ip' CNAME redirect could lead to a     crash. Thanks to Qifan Zhang, Palo Alto Networks, for the report. In addition, thanks to Xin Wang, Jiapeng     Li, and Jiajia Liu, Northwestern Polytechnical University, for also reporting this issue.
    - Fix CVE-2026-55973, 'dns-error-reporting: yes' leads to stack buffer overflow. Thanks to Qifan Zhang,     Palo Alto Networks, for the report.
    - Fix CVE-2026-55990, Packet of death for a DNSCrypt misconfigured Unbound. Thanks to Qifan Zhang, Palo     Alto Networks, for the report.
    - Fix CVE-2026-55991, Remote DNS-over-QUIC (DoQ) flow-control assertion failure in libngtcp2. Thanks to     Qifan Zhang, Palo Alto Networks, for the report. In addition, thanks to Xuanchao Xie, for also reporting     this issue.
    - Fix CVE-2026-56416, Possible heap buffer overflow when validator canonicalizes RDATA that contains     domain name. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-56444, Degradation of resolution service when 'discard-timeout' and 'serve-expired-client-     timeout' are combined in unusual configuration. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    In addition, thanks to Xin Wang, Jiapeng Li, and Jiajia Liu, Northwestern Polytechnical University, for     also reporting this issue. In addition, thanks to Haruki Oyama (Waseda University), for also reporting     this issue.

    Source: https://nlnetlabs.nl/projects/unbound/download/#unbound-1-25-2



Tenable has extracted the preceding description block directly from the Fedora 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 remote Fedora 43 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-3170ee6a1c advisory.

    Update to 1.25.2 (rhbz#2506061)

    Security fixes:

    - Fix CVE-2026-14586, Assertion in libngtcp2 when under pressure in high concurrency DNS-over-QUIC     environments. Thanks to Kunta Chu, Kaihua Wang, and Jianjun Chen from Tsinghua University, for the report.
    - Fix CVE-2026-32665, Remote DNS-over-QUIC denial of service due to `quic-size` budget bypass. Thanks to     N0zoM1z0 (https://github.com/N0zoM1z0) for the report. In addition, thanks to Kunta Chu, Kaihua Wang, and     Jianjun Chen from Tsinghua University, for also reporting this issue. In addition, thanks to Qifan Zhang,     Palo Alto Networks, for also reporting this issue. In addition, thanks to Xuanchao Xie, for also reporting     this issue.
    - Fix CVE-2026-40691, Packet of death for DNSCrypt over TCP. Thanks to Qifan Zhang, Palo Alto Networks,     for the report. In addition, thanks to Trung Nguyen (@everping) of CyStack, for also reporting this issue.
    - Fix CVE-2026-41637, Degradation of resolution service from improperly accounted client-terminated DNS-     over-QUIC queries. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-42955, Extra fix for CVE-2026-40622 to also clamp the TTL of A/AAAA records disallowing a     one-time 'ghost domain' delegation renewal via glue records. Thanks to Qifan Zhang, Palo Alto Networks,     for the report.
    - Fix CVE-2026-44621, Libunbound applications configured with 'unwanted-reply-threshold' could eventually     be abruptly terminated. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-44687, Off-by-one error in 'harden-below-nxdomain' logic can shadow a stub/forward zone by     a legitimate parent's NXDOMAIN. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-44690, Cross-zone wildcard cache poisoning via RRSIG.labels manipulation. Thanks to Qifan     Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-46582, A wildcard replay, as another piece of data, triggers poisoning in the serve expired     reply path. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50045, 'max-global-quota' reset by DNSSEC validation restarts. Thanks to Kunjie Shang,     University of Science and Technology of China, for the report.
    - Fix CVE-2026-50046, Possible heap use-after-free in an error path when a DoT forwarded query is jostled     out. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50243, 'response-ip'/'rpz' can rewrite BOGUS answers instead of returning SERVFAIL. Thanks     to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50248, BOGUS configured primary hostname accepted for XFR in auth/rpz zones. Thanks to     Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50251, Attacker supplied `0.0.0.0`/`::` glue triggers defensive full-cache flush. Thanks to     Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-50252, Possible cache poisoning attack by mapping source port population per thread. Thanks     to Inbal Schussheim and Amit Klein, Hebrew University, for the report.
    - Fix CVE-2026-52863, Memory corruption could lead to crash and denial of service. Thanks to Qifan Zhang,     Palo Alto Networks, for the report.
    - Fix CVE-2026-54478, DNS Cookie bypass when combined with proxy-protocol use. Thanks to Qifan Zhang, Palo     Alto Networks, for the report.
    - Fix CVE-2026-55708, Privacy/configuration issue when adding local data in views through 'unbound-     control'. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-55717, 'serve-expired-client-timeout' and 'response-ip' CNAME redirect could lead to a     crash. Thanks to Qifan Zhang, Palo Alto Networks, for the report. In addition, thanks to Xin Wang, Jiapeng     Li, and Jiajia Liu, Northwestern Polytechnical University, for also reporting this issue.
    - Fix CVE-2026-55973, 'dns-error-reporting: yes' leads to stack buffer overflow. Thanks to Qifan Zhang,     Palo Alto Networks, for the report.
    - Fix CVE-2026-55990, Packet of death for a DNSCrypt misconfigured Unbound. Thanks to Qifan Zhang, Palo     Alto Networks, for the report.
    - Fix CVE-2026-55991, Remote DNS-over-QUIC (DoQ) flow-control assertion failure in libngtcp2. Thanks to     Qifan Zhang, Palo Alto Networks, for the report. In addition, thanks to Xuanchao Xie, for also reporting     this issue.
    - Fix CVE-2026-56416, Possible heap buffer overflow when validator canonicalizes RDATA that contains     domain name. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    - Fix CVE-2026-56444, Degradation of resolution service when 'discard-timeout' and 'serve-expired-client-     timeout' are combined in unusual configuration. Thanks to Qifan Zhang, Palo Alto Networks, for the report.
    In addition, thanks to Xin Wang, Jiapeng Li, and Jiajia Liu, Northwestern Polytechnical University, for     also reporting this issue. In addition, thanks to Haruki Oyama (Waseda University), for also reporting     this issue.

    Source: https://nlnetlabs.nl/projects/unbound/download/#unbound-1-25-2



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

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

ID	Name	Product	Family	Published	Updated	Severity
445414	Alpine: multiple unbound packages, py3-unbound: security update to 1.25.2-r0	Tenable Self-Hosted Container Security	Alpine Linux Local Security Checks	7/29/2026	7/29/2026	high
445414	Alpine: multiple unbound packages, py3-unbound: security update to 1.25.2-r0	Tenable Cloud Security	Alpine Linux Local Security Checks	7/29/2026	7/29/2026	high
329494	Linux Distros Unpatched Vulnerability : CVE-2026-42955	Nessus	Misc.	7/25/2026	7/29/2026	low
330007	FreeBSD : unbound -- multiple vulnerabilities (f63b4b88-6901-4c12-b13d-5a821e25e9bf)	Nessus	FreeBSD Local Security Checks	7/26/2026	7/27/2026	high
330825	Fedora 44 : unbound (2026-e495bd59ef)	Nessus	Fedora Local Security Checks	7/30/2026	7/30/2026	high
331344	Fedora 43 : unbound (2026-3170ee6a1c)	Nessus	Fedora Local Security Checks	7/31/2026	7/31/2026	high

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