CVE-2026-7656— Zephyr 授权问题漏洞

Broken IPv6 Neighbor Discovery input validation allows spoofed RA/NS/NA acceptance in Zephyr net stack

The IPv6 Neighbor Discovery handlers in subsys/net/ip/ipv6_nbr.c (handle_ra_input, handle_ns_input, handle_na_input) used an incorrect boolean expression that combined the RFC 4861 validity checks with the ICMPv6 code check using the wrong operator precedence: the form was '((length/hop/source/target checks) && (icmp_hdr-code != 0))'. Because every legitimate ND message carries ICMPv6 code 0, an attacker setting code == 0 (the normal value) caused the entire predicate to evaluate false, so the packet was never dropped and all of the other checks were silently skipped. The bypassed checks include the mandatory Hop Limit == 255 verification (which proves an ND packet originated on-link and was not forwarded) and, for Router Advertisements, the requirement that the source be a link-local address, as well as multicast-target sanity checks. As a result, an adjacent on-link attacker — and, because the Hop-Limit-255 guard is bypassed, potentially a remote/off-link attacker whose packets would otherwise be rejected — can have forged Router Advertisement, Neighbor Solicitation, and Neighbor Advertisement messages accepted. A forged RA lets the attacker reconfigure the victim's default router, on-link prefixes (SLAAC), MTU, reachable/retransmit timers, and (with CONFIG_NET_IPV6_RA_RDNSS) DNS servers, while forged NS/NA enable neighbor-cache poisoning, enabling man-in-the-middle, traffic redirection, and denial of service. The flaw is an input-validation/authentication weakness rather than a memory-safety issue: the underlying packet-parsing primitives (net_pkt_get_data, net_pkt_read, net_pkt_skip) are independently bounds-safe and the validated 'length' is the true buffer length, so skipping the length check causes no out-of-bounds access. The defect has existed since the logic was introduced in 2018 and shipped in all releases through v4.4.0; it is fixed by splitting the condition so any failing check drops the packet.

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

控制流实现总是不正确

Zephyr 授权问题漏洞

Zephyr是Zephyr组织开源的一个可扩展的实时操作系统 (RTOS)。 Zephyr 1.14.0版本至4.4.0版本存在安全漏洞，该漏洞源于IPv6邻居发现处理程序中使用了错误的布尔表达式，可能导致相邻攻击者或远程攻击者绕过Hop Limit == 255等关键检查，接受伪造的路由器通告、邻居请求和邻居通告消息，从而实现中间人攻击、流量重定向和拒绝服务。

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