CVE-2026-15893
Açıklama (NVD)
net_if_ipv6_calc_reachable_time() in subsys/net/ip/net_if.c derives a randomized ND reachable time from ipv6->base_reachable_time as min_reachable + sys_rand32_get() % (max_reachable - min_reachable), where min_reachable = base/2 and max_reachable = 3*base/2 using integer division. When base_reachable_time is 1, both min_reachable and the modulus collapse so the function returns 0, and net_if_ipv6_set_reachable_time() stores that 0 into ipv6->reachable_time. The base_reachable_time is attacker-controlled: handle_ra_input() in subsys/net/ip/ipv6_nbr.c accepts the Reachable Time field of an incoming Router Advertisement whenever it is nonzero and <= MAX_REACHABLE_TIME, so a single unauthenticated, link-local RA carrying a Reachable Time of 1 drives the computed reachable time to 0. Router Advertisements are unauthenticated by default and require only adjacency to the target link. When a neighbor is subsequently confirmed reachable, net_ipv6_nbr_set_reachable_timer() reads the value and executes NET_ASSERT(time, "Zero reachable timeout!"). On builds with CONFIG_ASSERT enabled this triggers a fatal kernel assertion — a remote denial of service; on builds without assertions the reachable timer is armed with K_MSEC(0) and fires immediately, forcing reachable neighbors into perpetual re-solicitation (STALE), degrading Neighbor Discovery. The impact is limited to availability; there is no memory-safety, confidentiality, or integrity consequence.
Yayın: 14.09.2026 · Son değişiklik: 04.11.2026 · Zayıflık: CWE-617
CVSS 3.1 metrikleri
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
| Saldırı vektörü | Komşu ağ |
| Karmaşıklık | Düşük |
| Gereken yetki | Yok |
| Kullanıcı etkileşimi | Gerekmez |
| Kapsam | Değişmez |
| Gizlilik | Yok |
| Bütünlük | Yok |
| Erişilebilirlik | Yüksek |
Hesaplanan temel puan: 6.5. CVSS hesaplayıcıda incele