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

  - ipv4: udp: Create exceptions before socket matching Currently, when ICMP Fragmentation Needed and Redirect     Message packets are locally delivered and quote a UDP packet, a FIB nexthop exception (FNHE) is only     created if the kernel can match the UDP packet to an existing socket. This behavior allows off-path     attackers to conduct a side-channel attack on the FNHE cache in order to discover the ephemeral port used     by a connected UDP socket. Commit 6457378fe796 (ipv4: use siphash instead of Jenkins in fnhe_hashfun())     and commit 67d6d681e15b (ipv4: make exception cache less predictible) tried to mitigate such attacks by     making it harder for attackers to discover hash collisions in the FNHE cache and by randomizing the number     of exceptions a hash bucket can hold, respectively. Unfortunately, both of the mitigations can be     bypassed. Instead, mitigate such attacks by always creating a FNHE, even before trying to find a matching     socket. Do that by calling ipv4_update_pmtu() and ipv4_redirect(), the helpers used when the quoted packet     did not originate from a socket. This means that guesses (right or wrong) from an off-path attacker will     always result in a FNHE being created or updated in the cache that the attacker can observe. Pass an oif     of 0, in a similar fashion to icmp_err(). This is also the oif used by the socket path for sockets that     are not bound to a device. Note that this does not allow attackers to create FNHEs that they could not     create before, as both helpers can already be reached with little to no validation. For example, by     sending an ICMP error that quotes an ICMP Echo Reply or one that quotes a UDP source port that matches a     wildcard socket. Also note that in the good case (matched socket) the above scheme comes at the cost of an     extra route lookup, as the no socket helpers perform their own lookup before the one performed by     ipv4_sk_update_pmtu() / ipv4_sk_redirect(). When the two resolve to different nexthops, it also results in     two exceptions being created for the same destination IP. One in the FNHE cache of the nexthop resolved by     the no socket helpers and another in the FNHE cache of the nexthop used by the socket. (CVE-2026-99077)

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Linux Distros Unpatched Vulnerability : CVE-2026-99077

high Nessus Plugin ID 371481

Version 1.7