{ "schema_version": "1.6.1", "id": "RPI-CVE-2024-26852", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2024-26852" ], "published": "2024-04-17T10:17:34Z", "summary": "net/ipv6: avoid possible UAF in ip6_route_mpath_notify()", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/ipv6: avoid possible UAF in ip6_route_mpath_notify()\n\nsyzbot found another use-after-free in ip6_route_mpath_notify() [1]\n\nCommit f7225172f25a (\"net/ipv6: prevent use after free in\nip6_route_mpath_notify\") was not able to fix the root cause.\n\nWe need to defer the fib6_info_release() calls after\nip6_route_mpath_notify(), in the cleanup phase.\n\n[1]\nBUG: KASAN: slab-use-after-free in rt6_fill_node+0x1460/0x1ac0\nRead of size 4 at addr ffff88809a07fc64 by task syz-executor.2/23037\n\nCPU: 0 PID: 23037 Comm: syz-executor.2 Not tainted 6.8.0-rc4-syzkaller-01035-gea7f3cfaa588 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024\nCall Trace:\n \n __dump_stack lib/dump_stack.c:88 [inline]\n dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106\n print_address_description mm/kasan/report.c:377 [inline]\n print_report+0x167/0x540 mm/kasan/report.c:488\n kasan_report+0x142/0x180 mm/kasan/report.c:601\n rt6_fill_node+0x1460/0x1ac0\n inet6_rt_notify+0x13b/0x290 net/ipv6/route.c:6184\n ip6_route_mpath_notify net/ipv6/route.c:5198 [inline]\n ip6_route_multipath_add net/ipv6/route.c:5404 [inline]\n inet6_rtm_newroute+0x1d0f/0x2300 net/ipv6/route.c:5517\n rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597\n netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543\n netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]\n netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367\n netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908\n sock_sendmsg_nosec net/socket.c:730 [inline]\n __sock_sendmsg+0x221/0x270 net/socket.c:745\n ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584\n ___sys_sendmsg net/socket.c:2638 [inline]\n __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667\n do_syscall_64+0xf9/0x240\n entry_SYSCALL_64_after_hwframe+0x6f/0x77\nRIP: 0033:0x7f73dd87dda9\nCode: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007f73de6550c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e\nRAX: ffffffffffffffda RBX: 00007f73dd9ac050 RCX: 00007f73dd87dda9\nRDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000005\nRBP: 00007f73dd8ca47a R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\nR13: 000000000000006e R14: 00007f73dd9ac050 R15: 00007ffdbdeb7858\n \n\nAllocated by task 23037:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n poison_kmalloc_redzone mm/kasan/common.c:372 [inline]\n __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:389\n kasan_kmalloc include/linux/kasan.h:211 [inline]\n __do_kmalloc_node mm/slub.c:3981 [inline]\n __kmalloc+0x22e/0x490 mm/slub.c:3994\n kmalloc include/linux/slab.h:594 [inline]\n kzalloc include/linux/slab.h:711 [inline]\n fib6_info_alloc+0x2e/0xf0 net/ipv6/ip6_fib.c:155\n ip6_route_info_create+0x445/0x12b0 net/ipv6/route.c:3758\n ip6_route_multipath_add net/ipv6/route.c:5298 [inline]\n inet6_rtm_newroute+0x744/0x2300 net/ipv6/route.c:5517\n rtnetlink_rcv_msg+0x885/0x1040 net/core/rtnetlink.c:6597\n netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2543\n netlink_unicast_kernel net/netlink/af_netlink.c:1341 [inline]\n netlink_unicast+0x7ea/0x980 net/netlink/af_netlink.c:1367\n netlink_sendmsg+0xa3b/0xd70 net/netlink/af_netlink.c:1908\n sock_sendmsg_nosec net/socket.c:730 [inline]\n __sock_sendmsg+0x221/0x270 net/socket.c:745\n ____sys_sendmsg+0x525/0x7d0 net/socket.c:2584\n ___sys_sendmsg net/socket.c:2638 [inline]\n __sys_sendmsg+0x2b0/0x3a0 net/socket.c:2667\n do_syscall_64+0xf9/0x240\n entry_SYSCALL_64_after_hwframe+0x6f/0x77\n\nFreed by task 16:\n kasan_save_stack mm/kasan/common.c:47 [inline]\n kasan_save_track+0x3f/0x80 mm/kasan/common.c:68\n kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:640\n poison_slab_object+0xa6/0xe0 m\n---truncated---", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.21-1+rpt1", "1:6.1.47-1+rpt2", "1:6.1.47-1+rpt4", "1:6.1.54-1+rpt2", "1:6.1.58-1+rpt2", "1:6.1.63-1+rpt1", "1:6.1.73-1+rpt1", "1:6.6.20-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi1-rpi-v6", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi1-rpi-v7", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi1-rpi-v7l", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi1-rpi-v8", "binary_version": "1:6.1.21-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v6", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v7", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v7l", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi2-rpi-v8", "binary_version": "1:6.1.47-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-2712", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v6", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v7", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v7l", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi4-rpi-v8", "binary_version": "1:6.1.54-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-2712", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v6", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v7", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v7l", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi6-rpi-v8", "binary_version": "1:6.1.58-1+rpt2" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-2712", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v6", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v7", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v7l", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi7-rpi-v8", "binary_version": "1:6.1.63-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-2712", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v6", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v7", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v7l", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.1.0-rpi8-rpi-v8", "binary_version": "1:6.1.73-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-2712", "binary_version": "1:6.6.20-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-v6", "binary_version": "1:6.6.20-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-v7", "binary_version": "1:6.6.20-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-v7l", "binary_version": "1:6.6.20-1+rpt1" }, { "binary_name": "linux-image-6.6.20+rpt-rpi-v8", "binary_version": "1:6.6.20-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.1.21-1+rpt1": { "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed", "upstream_version": "6.1.21", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.82" }, "1:6.1.47-1+rpt2": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.82" }, "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.82", "compiled_filter": false }, "1:6.1.54-1+rpt2": { "linux_commit": "2906f7abdc03d4a92b6b0e2e0c87ea2a9dffe8f7", "upstream_version": "6.1.54", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.82" }, "1:6.1.58-1+rpt2": { "linux_commit": "ccf1586ad0663fa91238ac56abf6340d6d740d18", "upstream_version": "6.1.58", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.1.82" }, "1:6.1.63-1+rpt1": { "linux_commit": null, "upstream_version": "6.1.63", "assessment": "upstream version (no usable Linux commit)", "upstream_fixed": "6.1.82" }, "1:6.1.73-1+rpt1": { "linux_commit": null, "upstream_version": "6.1.73", "assessment": "upstream version (no usable Linux commit)", "upstream_fixed": "6.1.82" }, "1:6.6.20-1+rpt1": { "linux_commit": "6f16847710cc0502450788b9f12f0a14d3429668", "upstream_version": "6.6.20", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.6.22" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2024-26852" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/31ea5bcc7d4cd1423de6be327a2c034725704136" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/664f9c647260cc9d68b4e31d9899530d89dd045e" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/79ce2e54cc0ae366f45516c00bf1b19aa43e9abe" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/cae3303257950d03ffec2df4a45e836f10d26c24" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/394334fe2ae3b9f1e2332b873857e84cb28aac18" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/ed883060c38721ed828061f6c0c30e5147326c9a" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/61b34f73cdbdb8eaf9ea12e9e2eb3b29716c4dda" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/685f7d531264599b3f167f1e94bbd22f120e5fab" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T11:52:36Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "AV:L - The vulnerability is triggered by an RTM_NEWROUTE message sent over an AF_NETLINK/NETLINK_ROUTE socket via sendmsg(), which requires local access to the system. There is no remote packet-processing path into ip6_route_multipath_add().\nAC:L - The attacker creates both sides of the condition: they drop the last reference themselves and can widen the window arbitrarily by supplying many nexthops, by setting RTA_EXPIRES=0 so the non-rtnl gc softirq reaps the route, and by lowering net.ipv6.route.gc_interval inside their own netns, with unlimited retries. syzbot reproduced it, confirming reliable triggerability.\nPR:L - rtnetlink_rcv_msg() only requires netlink_net_capable(skb, CAP_NET_ADMIN), which is evaluated against the network namespace's user namespace, so any unprivileged local user obtains it with `unshare -Urn`. Multipath ECMP routes are addable in that namespace using RTNH_F_ONLINK gateways, which bypasses gateway reachability validation.\nUI:N - The entire sequence is performed by the attacker's own process in a single netlink transaction; no victim action, mount, or other interaction is needed.\nS:U - The use-after-free corrupts kernel heap memory and is exploited within the same kernel security authority; no VM, IOMMU, or hypervisor boundary is crossed.\nC:H - rt6_fill_node() reads the freed kmalloc-512 fib6_info and copies its contents into an RTM_NEWROUTE netlink message returned to the attacker's socket, including dereferencing pointers taken from freed memory such as rt->fib6_metrics (passed to rtnetlink_put_metrics()), rt->fib6_table, and rt->fib6_nh. Reclaiming the freed slot with controlled data turns this into an arbitrary kernel-memory read leaked directly to userspace.\nI:H - This is a use-after-free on a 512-byte kmalloc object that an unprivileged attacker can spray and reclaim, after which the kernel dereferences attacker-controlled pointers and performs a list_for_each_entry_safe() walk over the freed fib6_siblings list head. That yields controlled pointer traversal and corruption suitable for privilege escalation.\nA:H - The KASAN slab-use-after-free in rt6_fill_node() causes an oops/panic when the freed object is unmapped, poisoned, or reclaimed with invalid pointers, and it can be triggered repeatedly to reliably crash the kernel." } } }