PT-2026-66770 · Zephyrproject · Zephyr
CVE-2026-10686
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Publicado
2026-07-31
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Atualizado
2026-07-31
CVSS v3.1
5.8
Média
| Vetor | AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L |
Zephyr's IPv6 forwarding path re-sent routed unicast packets without ever decrementing the IPv6 hop limit. Both routing branches of ipv6 route packet() (subsys/net/ip) were affected: the explicit-route path (net route packet()) and the on-link cross-interface path (net route packet if()). Each set the packet forwarding flag and called net send data() with the hop limit untouched and no expiry check.
Per RFC 8200 the hop-limit decrement is the mechanism that bounds packet lifetime and terminates routing loops; without it, a device acting as an IPv6 router relays looping packets indefinitely. An on-path attacker who can induce or exploit a transient L3 loop turns it into a permanent forwarding storm, causing CPU/bandwidth resource exhaustion (availability DoS) on the forwarder and adjacent links; path-discovery and loop diagnostics that rely on hop-limit expiry are also defeated.
Affected configurations. In every affected release the forwarding path is reached via CONFIG NET ROUTE (enabled by default when CONFIG NET IPV6 NBR CACHE is set), together with CONFIG NET ROUTING for cross-interface routing. Note that CONFIG NET IPV6 FORWARDING and CONFIG NET IPV4 FORWARDING — which appear in the fix and in this advisory's evidence notes — were introduced after v4.4.0, when the routing options were split and renamed; they do not exist in any affected release. When auditing a v4.4.1-or-earlier configuration, look for CONFIG NET ROUTE and CONFIG NET ROUTING.
IPv4 is not affected in any release. The IPv4 forwarding path (net route ipv4 packet() in route ipv4.c) was added after v4.4.0 and has never shipped in a release. Its TTL decrement and IPv4 header-checksum recomputation landed on main as part of the same fix, so the evidence notes below discuss it, but no released version is reachable by way of IPv4.
Affected releases are v1.8.0 through v4.4.1: v1.8.0 introduced net route packet() and v2.2.0 added net route packet if(), and neither decremented the hop limit. v4.3.1 carries the explicit-route fix but not the on-link one, so it is affected as well. Fixed on main by 7d8f1afa7345 (explicit-route path) and 589eadc74efa (on-link path).
Correção
Infinite Loop
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