{"id":"CVE-2026-98508","summary":"drm/virtio: fix NULL pointer dereference on fence allocation failure","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/virtio: fix NULL pointer dereference on fence allocation failure\n\nvirtio_gpu_fence_alloc() can fail due to memory pressure and return NULL,\nbut its caller like virtio_gpu_init_submit() never checks it. Later,\nvirtio_gpu_init_submit() passes the NULL fence to\nvirtio_gpu_fence_event_create(), which unconditionally dereferences it.\n\nFound when fuzzing the virtio driver with Syzkaller:\n\n\tOops: general protection fault, probably for non-canonical address 0xdffffc0000000012: 0000 [#1] SMP KASAN NOPTI\n\tKASAN: null-ptr-deref in range [0x0000000000000090-0x0000000000000097]\n\tCPU: 1 UID: 0 PID: 9991 Comm: syz.0.121 Not tainted 7.2.0 #4 PREEMPT(full)\n\tHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014\n\tRIP: 0010:virtio_gpu_fence_event_create drivers/gpu/drm/virtio/virtgpu_submit.c:295 [inline]\n\tRIP: 0010:virtio_gpu_init_submit drivers/gpu/drm/virtio/virtgpu_submit.c:398 [inline]\n\tRIP: 0010:virtio_gpu_execbuffer_ioctl+0xc78/0x1aa0 drivers/gpu/drm/virtio/virtgpu_submit.c:505\n\tCode: 85 ed 0f 85 21 09 00 00 e8 05 5a c9 fb 48 8b 44 24 10 48 8d b8 90 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 \u003c80\u003e 3c 02 00 0f 85 9a 0d 00 00 48 8b 44 24 10 4c 89 b0 90 00 00 00\n\tRSP: 0018:ffffc900039dfad0 EFLAGS: 00010216\n\tRAX: dffffc0000000000 RBX: ffffc900039dfdd8 RCX: ffffffff85f6fd3d\n\tRDX: 0000000000000012 RSI: ffffffff85f6fd4b RDI: 0000000000000090\n\tRBP: 0000000000000000 R0virtio_gpu_virgl_process_cmd: ctrl 0x102, error 0x1203\n\tR10: 0000000000000000 R11: 0000000000000000 R12: ffff8880132c4000\n\tR13: 0000000000000000 R14: ffff888073b6c700 R15: 000000000000003b\n\tFS:  00007fab480b96c0(0000) GS:ffff8880eb6e9000(0000) knlGS:0000000000000000\n\tCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n\tCR2: 00007effbf5e55a8 CR3: 0000000048d19000 CR4: 0000000000350ef0\n\tCall Trace:\n\t\u003cTASK\u003e\n\tdrm_ioctl_kernel+0x1f4/0x3e0 drivers/gpu/drm/drm_ioctl.c:817\n\tdrm_ioctl+0x5f4/0xc70 drivers/gpu/drm/drm_ioctl.c:914\n\tvfs_ioctl fs/ioctl.c:51 [inline]\n\t__do_sys_ioctl fs/ioctl.c:597 [inline]\n\t__se_sys_ioctl fs/ioctl.c:583 [inline]\n\t__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583\n\tdo_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n\tdo_syscall_64+0x116/0x800 arch/x86/entry/syscall_64.c:94\n\tentry_SYSCALL_64_after_hwframe+0x77/0x7f\n\tRIP: 0033:0x7fab471a82bd\n\tCode: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48\n\tRSP: 002b:00007fab480b9018 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\n\tRAX: ffffffffffffffda RBX: 00007fab47435fa0 RCX: 00007fab471a82bd\n\tRDX: 00002000000000c0 RSI: 00000000c0406442 RDI: 0000000000000003\n\tRBP: 00007fab480b9080 R08: 0000000000000000 R09: 0000000000000000\n\tR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001\n\tR13: 00007fab47436038 R14: 00007fab47435fa0 R15: 00007ffe85ab0740\n\t\u003c/TASK\u003e\n\tModules linked in:\n\t---[ end trace 0000000000000000 ]---\n\tRIP: 0010:virtio_gpu_fence_event_create drivers/gpu/drm/virtio/virtgpu_submit.c:295 [inline]\n\tRIP: 0010:virtio_gpu_init_submit drivers/gpu/drm/virtio/virtgpu_submit.c:398 [inline]\n\tRIP: 0010:virtio_gpu_execbuffer_ioctl+0xc78/0x1aa0 drivers/gpu/drm/virtio/virtgpu_submit.c:505\n\tCode: 85 ed 0f 85 21 09 00 00 e8 05 5a c9 fb 48 8b 44 24 10 48 8d b8 90 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 \u003c80\u003e 3c 02 00 0f 85 9a 0d 00 00 48 8b 44 24 10 4c 89 b0 90 00 00 00\n\tRSP: 0018:ffffc900039dfad0 EFLAGS: 00010216\n\tRAX: dffffc0000000000 RBX: ffffc900039dfdd8 RCX: ffffffff85f6fd3d\n\tRDX: 0000000000000012 RSI: ffffffff85f6fd4b RDI: 0000000000000090\n\tRBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000\n\tR10: 0000000000000000 R11: 0000000000000000 R12: ffff8880132c4000\n\tR13: 0000000000000000 R14: ffff888073b6c700 R15: 000000000000003b\n\tFS:  00007fab480b96c0(0000) GS:ffff888098ae9000(0000) knlGS:00000000\n---truncated---","modified":"2026-10-19T02:46:26.500679307Z","published":"2026-10-18T15:17:15.082Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98508.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/846b3c64fe3e77d9db20a7e3e62dbbb637c773e1"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9571ab7493561afb4624d69572a7ebb67d76d10f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/a8b83ed4a4b1d04c756f53e375e86d3881f66e72"},{"type":"WEB","url":"https://git.kernel.org/stable/c/ecced0076b700b5896e52af10d0776be8be36b0d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f2f1683955b95c9b958069da3050f7e8e129ff88"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98508.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98508"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"70d1ace56db6c79d39dbe9c0d5244452b67e2fde"},{"fixed":"9571ab7493561afb4624d69572a7ebb67d76d10f"},{"fixed":"a8b83ed4a4b1d04c756f53e375e86d3881f66e72"},{"fixed":"f2f1683955b95c9b958069da3050f7e8e129ff88"},{"fixed":"ecced0076b700b5896e52af10d0776be8be36b0d"},{"fixed":"846b3c64fe3e77d9db20a7e3e62dbbb637c773e1"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.1.54"},{"fixed":"6.2"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"6.5.4"},{"fixed":"6.6"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"98d3e7c5f757577394f036e0301db9e570342566"}]},{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"4037dcd70c3335600a2a95ec6229d70859bd37a1"}]}],"versions":["v6.1.190","v6.1.189","v6.1.188","v6.1.187","v6.1.186","v6.1.185","v6.1.184","v6.1.183","v6.1.182","v6.1.181","v6.1.180","v6.1.179","v6.1.178","v6.1.177","v6.1.176","v6.1.175","v6.1.174","v6.1.173","v6.1.172","v6.1.171","v6.1.170","v6.1.169","v6.1.168","v6.1.167","v6.1.166","v6.1.165","v6.1.164","v6.1.163","v6.1.162","v6.1.161","v6.1.160","v6.1.159","v6.1.158","v6.1.157","v6.1.156","v6.1.155","v6.1.154","v6.1.153","v6.1.152","v6.1.151","v6.1.150","v6.1.149","v6.1.148","v6.1.147","v6.1.146","v6.1.145","v6.1.144","v6.1.143","v6.1.142","v6.1.141","v6.1.140","v6.1.139","v6.1.138","v6.1.137","v6.1.136","v6.1.135","v6.1.134","v6.1.133","v6.1.132","v6.1.131","v6.1.130","v6.1.129","v6.1.128","v6.1.127","v6.1.126","v6.1.125","v6.1.124","v6.1.123","v6.1.122","v6.1.121","v6.1.120","v6.1.119","v6.1.118","v6.1.117","v6.1.116","v6.1.115","v6.1.114","v6.1.113","v6.1.112","v6.1.111","v6.1.110","v6.1.109","v6.1.108","v6.1.107","v6.1.106","v6.1.105","v6.1.104","v6.1.103","v6.1.102","v6.1.101","v6.1.100","v6.1.99","v6.1.98","v6.1.97","v6.1.96","v6.1.95","v6.1.94","v6.1.93","v6.1.92","v6.1.91","v6.1.90","v6.1.89","v6.1.88","v6.1.87","v6.1.86","v6.1.85","v6.1.84","v6.1.83","v6.1.82","v6.1.81","v6.1.80","v6.1.79","v6.1.78","v6.1.77","v6.1.76","v6.1.75","v6.1.74","v6.1.73","v6.1.72","v6.1.71","v6.1.70","v6.1.69","v6.1.68","v6.1.67","v6.1.66","v6.1.65","v6.1.64","v6.1.63","v6.1.62","v6.1.61","v6.1.60","v6.1.59","v6.1.58","v6.1.57","v6.1.56","v6.1.55","v6.1.54","v6.5.13","v6.5.12","v6.5.11","v6.5.10","v6.5.9","v6.5.8","v6.5.7","v6.5.6","v6.5.5","v6.5.4"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98508.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.6.0"},{"fixed":"6.6.158"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.112"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.55"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.9"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98508.json"}}],"schema_version":"1.9.0"}