CVE-2026-23200

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ipv6: Fix ECMP sibling count mismatch when clearing RTF_ADDRCONF<br /> <br /> syzbot reported a kernel BUG in fib6_add_rt2node() when adding an IPv6<br /> route. [0]<br /> <br /> Commit f72514b3c569 ("ipv6: clear RA flags when adding a static<br /> route") introduced logic to clear RTF_ADDRCONF from existing routes<br /> when a static route with the same nexthop is added. However, this<br /> causes a problem when the existing route has a gateway.<br /> <br /> When RTF_ADDRCONF is cleared from a route that has a gateway, that<br /> route becomes eligible for ECMP, i.e. rt6_qualify_for_ecmp() returns<br /> true. The issue is that this route was never added to the<br /> fib6_siblings list.<br /> <br /> This leads to a mismatch between the following counts:<br /> <br /> - The sibling count computed by iterating fib6_next chain, which<br /> includes the newly ECMP-eligible route<br /> <br /> - The actual siblings in fib6_siblings list, which does not include<br /> that route<br /> <br /> When a subsequent ECMP route is added, fib6_add_rt2node() hits<br /> BUG_ON(sibling-&gt;fib6_nsiblings != rt-&gt;fib6_nsiblings) because the<br /> counts don&amp;#39;t match.<br /> <br /> Fix this by only clearing RTF_ADDRCONF when the existing route does<br /> not have a gateway. Routes without a gateway cannot qualify for ECMP<br /> anyway (rt6_qualify_for_ecmp() requires fib_nh_gw_family), so clearing<br /> RTF_ADDRCONF on them is safe and matches the original intent of the<br /> commit.<br /> <br /> [0]:<br /> kernel BUG at net/ipv6/ip6_fib.c:1217!<br /> Oops: invalid opcode: 0000 [#1] SMP KASAN PTI<br /> CPU: 0 UID: 0 PID: 6010 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)<br /> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025<br /> RIP: 0010:fib6_add_rt2node+0x3433/0x3470 net/ipv6/ip6_fib.c:1217<br /> [...]<br /> Call Trace:<br /> <br /> fib6_add+0x8da/0x18a0 net/ipv6/ip6_fib.c:1532<br /> __ip6_ins_rt net/ipv6/route.c:1351 [inline]<br /> ip6_route_add+0xde/0x1b0 net/ipv6/route.c:3946<br /> ipv6_route_ioctl+0x35c/0x480 net/ipv6/route.c:4571<br /> inet6_ioctl+0x219/0x280 net/ipv6/af_inet6.c:577<br /> sock_do_ioctl+0xdc/0x300 net/socket.c:1245<br /> sock_ioctl+0x576/0x790 net/socket.c:1366<br /> vfs_ioctl fs/ioctl.c:51 [inline]<br /> __do_sys_ioctl fs/ioctl.c:597 [inline]<br /> __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583<br /> do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]<br /> do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94<br /> entry_SYSCALL_64_after_hwframe+0x77/0x7f