{"id":"CVE-2024-40958","title":"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 re…","summary":"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 re…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 5.2, < 5.4.279","linux_kernel >= 5.5, < 5.10.221","linux_kernel >= 5.11, < 5.15.162","linux_kernel >= 5.16, < 6.1.96","linux_kernel >= 6.2, < 6.6.36","linux_kernel >= 6.7, < 6.9.7","linux_kernel = 6.10"],"patched":["linux_kernel 6.9.7"],"published":"2024-07-12","updated":"2026-10-15","sourceUpdated":"2026-10-15T01:18:38.423","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2024-40958","references":[{"url":"https://git.kernel.org/stable/c/1b631bffcb2c09551888f3c723f4365c91fe05ef","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2b82028a1f5ee3a8e04090776b10c534144ae77b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3a6cd326ead7c8bb1f64486789a01974a9f1ad55","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/3af28df0d883e8c89a29ac31bc65f9023485743b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/cb7f811f638a14590ff98f53c6dd1fb54627d940","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ef0394ca25953ea0eddcc82feae1f750451f1876","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ff960f9d3edbe08a736b5a224d91a305ccc946b0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/1b631bffcb2c09551888f3c723f4365c91fe05ef","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/2b82028a1f5ee3a8e04090776b10c534144ae77b","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/3a6cd326ead7c8bb1f64486789a01974a9f1ad55","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/3af28df0d883e8c89a29ac31bc65f9023485743b","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/cb7f811f638a14590ff98f53c6dd1fb54627d940","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/ef0394ca25953ea0eddcc82feae1f750451f1876","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/ff960f9d3edbe08a736b5a224d91a305ccc946b0","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-265688.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-355557.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-613116.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00269,"epssPercentile":0.19,"ingestedAt":"2026-10-15T03:30:12.722Z","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2024-09-10T17:03:35.616951Z"},"slug":"CVE-2024-40958","body":"## Overview\n\nIn 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 <TASK>\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 </TASK>\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\n\n## Affected\n\n- `linux_kernel >= 5.2, < 5.4.279`\n- `linux_kernel >= 5.5, < 5.10.221`\n- `linux_kernel >= 5.11, < 5.15.162`\n- `linux_kernel >= 5.16, < 6.1.96`\n- `linux_kernel >= 6.2, < 6.6.36`\n- `linux_kernel >= 6.7, < 6.9.7`\n- `linux_kernel = 6.10`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.9.7`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}