{"id":"CVE-2024-40958","revision":"f7f3ff66ce364984b91dce1d7c8db01e","records":[{"revision":"f7f3ff66ce364984b91dce1d7c8db01e","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2024-40958","aliases":[],"title":"netns: Make get_net_ns() handle zero refcount net","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetns: Make get_net_ns() handle zero refcount net\n\nSyzkaller hit a warning:\nrefcount_t: addition on 0; use-after-free.\nWARNING: CPU: 3 PID: 7890 at lib/refcount.c:25 refcount_warn_saturate+0xdf/0x1d0\nModules linked in:\nCPU: 3 PID: 7890 Comm: tun Not tainted 6.10.0-rc3-00100-gcaa4f9578aba-dirty #310\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\nRIP: 0010:refcount_warn_saturate+0xdf/0x1d0\nCode: 41 49 04 31 ff 89 de e8 9f 1e cd fe 84 db 75 9c e8 76 26 cd fe c6 05 b6 41 49 04 01 90 48 c7 c7 b8 8e 25 86 e8 d2 05 b5 fe 90 <0f> 0b 90 90 e9 79 ff ff ff e8 53 26 cd fe 0f b6 1\nRSP: 0018:ffff8881067b7da0 EFLAGS: 00010286\nRAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff811c72ac\nRDX: ffff8881026a2140 RSI: ffffffff811c72b5 RDI: 0000000000000001\nRBP: ffff8881067b7db0 R08: 0000000000000000 R09: 205b5d3730353139\nR10: 0000000000000000 R11: 205d303938375420 R12: ffff8881086500c4\nR13: ffff8881086500c4 R14: ffff8881086500b0 R15: ffff888108650040\nFS: 00007f5b2961a4c0(0000) GS:ffff88823bd00000(0000) knlGS:0000000000000000\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 000055d7ed36fd18 CR3: 00000001482f6000 CR4: 00000000000006f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n \n ? show_regs+0xa3/0xc0\n ? __warn+0xa5/0x1c0\n ? refcount_warn_saturate+0xdf/0x1d0\n ? report_bug+0x1fc/0x2d0\n ? refcount_warn_saturate+0xdf/0x1d0\n ? handle_bug+0xa1/0x110\n ? exc_invalid_op+0x3c/0xb0\n ? asm_exc_invalid_op+0x1f/0x30\n ? __warn_printk+0xcc/0x140\n ? __warn_printk+0xd5/0x140\n ? refcount_warn_saturate+0xdf/0x1d0\n get_net_ns+0xa4/0xc0\n ? __pfx_get_net_ns+0x10/0x10\n open_related_ns+0x5a/0x130\n __tun_chr_ioctl+0x1616/0x2370\n ? __sanitizer_cov_trace_switch+0x58/0xa0\n ? __sanitizer_cov_trace_const_cmp2+0x1c/0x30\n ? __pfx_tun_chr_ioctl+0x10/0x10\n tun_chr_ioctl+0x2f/0x40\n __x64_sys_ioctl+0x11b/0x160\n x64_sys_call+0x1211/0x20d0\n do_syscall_64+0x9e/0x1d0\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\nRIP: 0033:0x7f5b28f165d7\nCode: b3 66 90 48 8b 05 b1 48 2d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 81 48 2d 00 8\nRSP: 002b:00007ffc2b59c5e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\nRAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f5b28f165d7\nRDX: 0000000000000000 RSI: 00000000000054e3 RDI: 0000000000000003\nRBP: 00007ffc2b59c650 R08: 00007f5b291ed8c0 R09: 00007f5b2961a4c0\nR10: 0000000029690010 R11: 0000000000000246 R12: 0000000000400730\nR13: 00007ffc2b59cf40 R14: 0000000000000000 R15: 0000000000000000\n \nKernel panic - not syncing: kernel: panic_on_warn set ...\n\nThis is trigger as below:\n ns0 ns1\ntun_set_iff() //dev is tun0\n tun->dev = dev\n//ip link set tun0 netns ns1\n put_net() //ref is 0\n__tun_chr_ioctl() //TUNGETDEVNETNS\n net = dev_net(tun->dev);\n open_related_ns(&net->ns, get_net_ns); //ns1\n get_net_ns()\n get_net() //addition on 0\n\nUse maybe_get_net() in get_net_ns in case net's ref is zero to fix this","state":0,"publishedAt":"2024-07-12T12:32:00.431+00:00","modifiedAt":"2026-10-15T00:45:50.378+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/core/net_namespace.c\"\n ],\n \"versions\": [\n {\n \"version\": \"0c3e0e3bb623c3735b8c9ab8aa8332f944f83a9f\",\n \"lessThan\": \"3a6cd326ead7c8bb1f64486789a01974a9f1ad55\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0c3e0e3bb623c3735b8c9ab8aa8332f944f83a9f\",\n \"lessThan\": \"2b82028a1f5ee3a8e04090776b10c534144ae77b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0c3e0e3bb623c3735b8c9ab8aa8332f944f83a9f\",\n \"lessThan\": \"cb7f811f638a14590ff98f53c6dd1fb54627d940\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0c3e0e3bb623c3735b8c9ab8aa8332f944f83a9f\",\n \"lessThan\": \"1b631bffcb2c09551888f3c723f4365c91fe05ef\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0c3e0e3bb623c3735b8c9ab8aa8332f944f83a9f\",\n \"lessThan\": \"ef0394ca25953ea0eddcc82feae1f750451f1876\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0c3e0e3bb623c3735b8c9ab8aa8332f944f83a9f\",\n \"lessThan\": \"3af28df0d883e8c89a29ac31bc65f9023485743b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0c3e0e3bb623c3735b8c9ab8aa8332f944f83a9f\",\n \"lessThan\": \"ff960f9d3edbe08a736b5a224d91a305ccc946b0\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/core/net_namespace.c\"\n ],\n \"versions\": [\n {\n \"version\": \"5.2\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"5.2\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.4.279\",\n \"lessThanOrEqual\": \"5.4.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.221\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.162\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.96\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.36\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.9.7\",\n \"lessThanOrEqual\": \"6.9.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.10\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","score":7.8,"severity":"HIGH"}],"references":["https://git.kernel.org/stable/c/3a6cd326ead7c8bb1f64486789a01974a9f1ad55","https://git.kernel.org/stable/c/2b82028a1f5ee3a8e04090776b10c534144ae77b","https://git.kernel.org/stable/c/cb7f811f638a14590ff98f53c6dd1fb54627d940","https://git.kernel.org/stable/c/1b631bffcb2c09551888f3c723f4365c91fe05ef","https://git.kernel.org/stable/c/ef0394ca25953ea0eddcc82feae1f750451f1876","https://git.kernel.org/stable/c/3af28df0d883e8c89a29ac31bc65f9023485743b","https://git.kernel.org/stable/c/ff960f9d3edbe08a736b5a224d91a305ccc946b0"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2024-40958","license":"CVE Program Terms of Use","key":"cve-program:CVE-2024-40958","identifiers":["CVE-2024-40958"]},"retained":false,"historicalAffected":[]}],"coverage":[]}