In the Linux kernel, the following vulnerability has been resolved: net/ip6_tunnel: Prevent perpetual tunnel growth Similarly to ipv4 tunnel, ipv6 version updates dev->needed_headroom, too. While ipv4 tunnel headroom adjustment growth was limited in commit 5ae1e9922bbd ("net: ip_tunnel: prevent perpetual headroom growth"), ipv6 tunnel yet increases the headroom without any ceiling. Reflect ipv4 tunnel headroom adjustment limit on ipv6 version. Credits to Francesco Ruggeri, who was originally debugging this issue and wrote local Arista-specific patch and a reproducer.

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4379 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-4379-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                        Ben Hutchings     November 25, 2025                             https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : linux-6.1     Version        : 6.1.158-1~deb11u1     CVE ID         : CVE-2025-21861 CVE-2025-39929 CVE-2025-39931 CVE-2025-39934                      CVE-2025-39937 CVE-2025-39938 CVE-2025-39942 CVE-2025-39943                      CVE-2025-39944 CVE-2025-39945 CVE-2025-39946 CVE-2025-39949                      CVE-2025-39951 CVE-2025-39953 CVE-2025-39955 CVE-2025-39957                      CVE-2025-39964 CVE-2025-39967 CVE-2025-39968 CVE-2025-39969                      CVE-2025-39970 CVE-2025-39971 CVE-2025-39972 CVE-2025-39973                      CVE-2025-39977 CVE-2025-39978 CVE-2025-39980 CVE-2025-39982                      CVE-2025-39985 CVE-2025-39986 CVE-2025-39987 CVE-2025-39988                      CVE-2025-39993 CVE-2025-39994 CVE-2025-39995 CVE-2025-39996                      CVE-2025-39998 CVE-2025-40001 CVE-2025-40006 CVE-2025-40008                      CVE-2025-40010 CVE-2025-40011 CVE-2025-40013 CVE-2025-40018                      CVE-2025-40019 CVE-2025-40020 CVE-2025-40021 CVE-2025-40022                      CVE-2025-40026 CVE-2025-40027 CVE-2025-40029 CVE-2025-40030                      CVE-2025-40032 CVE-2025-40035 CVE-2025-40036 CVE-2025-40040                      CVE-2025-40042 CVE-2025-40043 CVE-2025-40044 CVE-2025-40048                      CVE-2025-40049 CVE-2025-40051 CVE-2025-40053 CVE-2025-40055                      CVE-2025-40056 CVE-2025-40060 CVE-2025-40062 CVE-2025-40068                      CVE-2025-40070 CVE-2025-40078 CVE-2025-40080 CVE-2025-40081                      CVE-2025-40084 CVE-2025-40085 CVE-2025-40087 CVE-2025-40088                      CVE-2025-40092 CVE-2025-40093 CVE-2025-40094 CVE-2025-40095                      CVE-2025-40096 CVE-2025-40099 CVE-2025-40100 CVE-2025-40103                      CVE-2025-40104 CVE-2025-40105 CVE-2025-40106 CVE-2025-40107                      CVE-2025-40109 CVE-2025-40111 CVE-2025-40112 CVE-2025-40115                      CVE-2025-40116 CVE-2025-40118 CVE-2025-40120 CVE-2025-40121                      CVE-2025-40123 CVE-2025-40124 CVE-2025-40125 CVE-2025-40126                      CVE-2025-40127 CVE-2025-40134 CVE-2025-40140 CVE-2025-40141                      CVE-2025-40153 CVE-2025-40154 CVE-2025-40156 CVE-2025-40167                      CVE-2025-40171 CVE-2025-40173 CVE-2025-40176 CVE-2025-40178                      CVE-2025-40179 CVE-2025-40183 CVE-2025-40186 CVE-2025-40187                      CVE-2025-40188 CVE-2025-40190 CVE-2025-40193 CVE-2025-40194                      CVE-2025-40197 CVE-2025-40198 CVE-2025-40200 CVE-2025-40201                      CVE-2025-40202 CVE-2025-40204 CVE-2025-40205 CVE-2025-40207

    Several vulnerabilities have been discovered in the Linux kernel that     may lead to a privilege escalation, denial of service or information     leaks.

    For Debian 11 bullseye, these problems have been fixed in version     6.1.158-1~deb11u1.  This version additionally includes many more bug     fixes from stable updates 6.1.154-6.1.158.

    We recommend that you upgrade your linux-6.1 packages.

    For the detailed security status of linux-6.1 please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/linux-6.1

    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 these issues but has instead relied only on the application's self-reported version number.

An update of the linux package has been released.

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

  - net/ip6_tunnel: Prevent perpetual tunnel growth Similarly to ipv4 tunnel, ipv6 version updates     dev->needed_headroom, too. While ipv4 tunnel headroom adjustment growth was limited in commit 5ae1e9922bbd     (net: ip_tunnel: prevent perpetual headroom growth), ipv6 tunnel yet increases the headroom without any     ceiling. Reflect ipv4 tunnel headroom adjustment limit on ipv6 version. Credits to Francesco Ruggeri, who     was originally debugging this issue and wrote local Arista-specific patch and a reproducer.
    (CVE-2025-40173)

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

ID	Name	Product	Family	Severity
276782	Debian dla-4379 : linux-config-6.1 - security update	Nessus	Debian Local Security Checks	medium
275495	Photon OS 5.0: Linux PHSA-2025-5.0-0677	Nessus	PhotonOS Local Security Checks	medium
275219	Linux Distros Unpatched Vulnerability : CVE-2025-40173	Nessus	Misc.	medium

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