{"id":"CVE-2025-37961","summary":"ipvs: fix uninit-value for saddr in do_output_route4","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nipvs: fix uninit-value for saddr in do_output_route4\n\nsyzbot reports for uninit-value for the saddr argument [1].\ncommit 4754957f04f5 (\"ipvs: do not use random local source address for\ntunnels\") already implies that the input value of saddr\nshould be ignored but the code is still reading it which can prevent\nto connect the route. Fix it by changing the argument to ret_saddr.\n\n[1]\nBUG: KMSAN: uninit-value in do_output_route4+0x42c/0x4d0 net/netfilter/ipvs/ip_vs_xmit.c:147\n do_output_route4+0x42c/0x4d0 net/netfilter/ipvs/ip_vs_xmit.c:147\n __ip_vs_get_out_rt+0x403/0x21d0 net/netfilter/ipvs/ip_vs_xmit.c:330\n ip_vs_tunnel_xmit+0x205/0x2380 net/netfilter/ipvs/ip_vs_xmit.c:1136\n ip_vs_in_hook+0x1aa5/0x35b0 net/netfilter/ipvs/ip_vs_core.c:2063\n nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]\n nf_hook_slow+0xf7/0x400 net/netfilter/core.c:626\n nf_hook include/linux/netfilter.h:269 [inline]\n __ip_local_out+0x758/0x7e0 net/ipv4/ip_output.c:118\n ip_local_out net/ipv4/ip_output.c:127 [inline]\n ip_send_skb+0x6a/0x3c0 net/ipv4/ip_output.c:1501\n udp_send_skb+0xfda/0x1b70 net/ipv4/udp.c:1195\n udp_sendmsg+0x2fe3/0x33c0 net/ipv4/udp.c:1483\n inet_sendmsg+0x1fc/0x280 net/ipv4/af_inet.c:851\n sock_sendmsg_nosec net/socket.c:712 [inline]\n __sock_sendmsg+0x267/0x380 net/socket.c:727\n ____sys_sendmsg+0x91b/0xda0 net/socket.c:2566\n ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2620\n __sys_sendmmsg+0x41d/0x880 net/socket.c:2702\n __compat_sys_sendmmsg net/compat.c:360 [inline]\n __do_compat_sys_sendmmsg net/compat.c:367 [inline]\n __se_compat_sys_sendmmsg net/compat.c:364 [inline]\n __ia32_compat_sys_sendmmsg+0xc8/0x140 net/compat.c:364\n ia32_sys_call+0x3ffa/0x41f0 arch/x86/include/generated/asm/syscalls_32.h:346\n do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]\n __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/syscall_32.c:306\n do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331\n do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369\n entry_SYSENTER_compat_after_hwframe+0x84/0x8e\n\nUninit was created at:\n slab_post_alloc_hook mm/slub.c:4167 [inline]\n slab_alloc_node mm/slub.c:4210 [inline]\n __kmalloc_cache_noprof+0x8fa/0xe00 mm/slub.c:4367\n kmalloc_noprof include/linux/slab.h:905 [inline]\n ip_vs_dest_dst_alloc net/netfilter/ipvs/ip_vs_xmit.c:61 [inline]\n __ip_vs_get_out_rt+0x35d/0x21d0 net/netfilter/ipvs/ip_vs_xmit.c:323\n ip_vs_tunnel_xmit+0x205/0x2380 net/netfilter/ipvs/ip_vs_xmit.c:1136\n ip_vs_in_hook+0x1aa5/0x35b0 net/netfilter/ipvs/ip_vs_core.c:2063\n nf_hook_entry_hookfn include/linux/netfilter.h:154 [inline]\n nf_hook_slow+0xf7/0x400 net/netfilter/core.c:626\n nf_hook include/linux/netfilter.h:269 [inline]\n __ip_local_out+0x758/0x7e0 net/ipv4/ip_output.c:118\n ip_local_out net/ipv4/ip_output.c:127 [inline]\n ip_send_skb+0x6a/0x3c0 net/ipv4/ip_output.c:1501\n udp_send_skb+0xfda/0x1b70 net/ipv4/udp.c:1195\n udp_sendmsg+0x2fe3/0x33c0 net/ipv4/udp.c:1483\n inet_sendmsg+0x1fc/0x280 net/ipv4/af_inet.c:851\n sock_sendmsg_nosec net/socket.c:712 [inline]\n __sock_sendmsg+0x267/0x380 net/socket.c:727\n ____sys_sendmsg+0x91b/0xda0 net/socket.c:2566\n ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2620\n __sys_sendmmsg+0x41d/0x880 net/socket.c:2702\n __compat_sys_sendmmsg net/compat.c:360 [inline]\n __do_compat_sys_sendmmsg net/compat.c:367 [inline]\n __se_compat_sys_sendmmsg net/compat.c:364 [inline]\n __ia32_compat_sys_sendmmsg+0xc8/0x140 net/compat.c:364\n ia32_sys_call+0x3ffa/0x41f0 arch/x86/include/generated/asm/syscalls_32.h:346\n do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]\n __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/syscall_32.c:306\n do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331\n do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369\n entry_SYSENTER_compat_after_hwframe+0x84/0x8e\n\nCPU: 0 UID: 0 PID: 22408 Comm: syz.4.5165 Not tainted 6.15.0-rc3-syzkaller-00019-gbc3372351d0c #0 PREEMPT(undef)\nHardware name: Google Google Compute Engi\n---truncated---","modified":"2026-07-15T01:49:16.359332832Z","published":"2025-05-20T16:01:53.940Z","related":["SUSE-SU-2025:02249-1","SUSE-SU-2025:02254-1","SUSE-SU-2025:02307-1","SUSE-SU-2025:02333-1","SUSE-SU-2025:02334-1","SUSE-SU-2025:02335-1","SUSE-SU-2025:02538-1","SUSE-SU-2025:02923-1","SUSE-SU-2025:20475-1","SUSE-SU-2025:20483-1","SUSE-SU-2025:20493-1","SUSE-SU-2025:20498-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37961.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0160ac84fb03a0bd8dce8a42cb25bfaeedd110f4"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7d0032112a0380d0b8d7c9005f621928a9b9fc76"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a3a1b784791a3cbfc6e05c4d8a3c321ac5136e25"},{"type":"WEB","url":"https://git.kernel.org/stable/c/adbc8cc1162951cb152ed7f147d5fbd35ce3e62f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/e34090d7214e0516eb8722aee295cb2507317c07"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/08/msg00010.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/37xxx/CVE-2025-37961.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-37961"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4754957f04f5f368792a0eb7dab0ae89fb93dcfd"},{"fixed":"7d0032112a0380d0b8d7c9005f621928a9b9fc76"},{"fixed":"adbc8cc1162951cb152ed7f147d5fbd35ce3e62f"},{"fixed":"0160ac84fb03a0bd8dce8a42cb25bfaeedd110f4"},{"fixed":"a3a1b784791a3cbfc6e05c4d8a3c321ac5136e25"},{"fixed":"e34090d7214e0516eb8722aee295cb2507317c07"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"0"},{"last_affected":"212c45ac20229c1752dd56fa38e9a8d57127974b"},{"last_affected":"2f0c79dd1e9d55a279b0a8e363717b7a896fe7b4"},{"last_affected":"cc2b6a186da7580d4557e7175c5ab4b18d9a57f0"},{"last_affected":"e89e653311ac2c9f37ceb778212ae4dbe1104091"},{"last_affected":"f1d62fb20245bc89d6ba93d829763450250a592b"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3.10.91"},{"fixed":"3.11"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3.12.50"},{"fixed":"3.13"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3.14.55"},{"fixed":"3.15"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"3.18.23"},{"fixed":"3.19"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4.1.11"},{"fixed":"4.2"}]}],"versions":["v4.1.10","v3.14.54","v3.10.90","v3.18.22","v3.12.49","v4.1.9","v3.10.89","v3.14.53","v4.1.8","v4.1.7","v3.14.52","v3.10.88","v3.12.48","v3.14.51","v3.10.87","v4.1.6","v3.18.21","v3.12.47","v3.18.20","v4.0-rc5","v4.1.5","v3.14.50","v3.10.86","v4.1.4","v3.14.49","v3.10.85","v3.12.46","v3.18.19","v3.14.48","v3.10.84","v4.1.3","v3.12.45","v4.1.2","v4.1-rc2","v4.1","v3.18.18","v3.10.83","v3.14.47","v4.1.1","v4.1-rc1","v3.14.46","v3.10.82","v3.14.45","v3.10.81","v3.18.17","v3.12.44","v3.14.44","v3.10.80","v4.1-rc8","v4.1-rc7","v4.1-rc6","v3.18.16","v3.18.15","v4.1-rc3","v4.1-rc4","v3.14.43","v3.10.79","v4.0","v4.1-rc5","v3.18.14","v3.12.43","v3.14.42","v3.10.78","v3.14.41","v3.10.77","v3.18.13","v3.14.40","v3.10.76","v3.12.42","v3.12.41","v3.10.75","v3.14.39","v4.0-rc1","v3.18.12","v3.14.38","v3.10.74","v4.0-rc2","v3.12.40","v3.14.37","v3.10.73","v4.0-rc7","v3.18.11","v3.12.39","v4.0-rc3","v4.0-rc6","v4.0-rc4","v3.14.36","v3.10.72","v3.19","v3.18.10","v3.14.35","v3.10.71","v3.18.9","v3.18.8","v3.14.34","v3.10.70","v3.12.38","v3.14.33","v3.18.7","v3.10.69","v3.19-rc7","v3.19-rc5","v3.19-rc1","v3.18.6","v3.14.32","v3.10.68","v3.18.5","v3.14.31","v3.10.67","v3.19-rc6","v3.19-rc4","v3.12.37","v3.10.66","v3.14.30","v3.18.4","v3.18.3","v3.14.29","v3.10.65","v3.18-rc1","v3.19-rc3","v3.19-rc2","v3.18.2","v3.14.28","v3.10.64","v3.12.36","v3.18.1","v3.14.27","v3.10.63","v3.18","v3.12.35","v3.14.26","v3.10.62","v3.18-rc7","v3.14.25","v3.10.61","v3.12.34","v3.18-rc6","v3.18-rc2","v3.18-rc3","v3.18-rc4","v3.18-rc5","v3.14.24","v3.10.60","v3.12.33","v3.17","v3.14.23","v3.10.59","v3.12.32","v3.14.22","v3.10.58","v3.17-rc1","v3.12.31","v3.14.21","v3.10.57","v3.17-rc7","v3.14.20","v3.10.56","v3.17-rc2","v3.10.55","v3.14.19","v3.17-rc4","v3.16","v3.17-rc5","v3.17-rc6","v3.12.30","v3.12.29","v3.14.18","v3.10.54","v3.17-rc3","v3.12.28","v3.14.17","v3.10.53","v3.12.27","v3.16-rc7","v3.14.16","v3.10.52","v3.14.15","v3.10.51","v3.16-rc1","v3.16-rc3","v3.10.50","v3.14.14","v3.12.26","v3.1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