{"id":"CVE-2026-98508","kind":"vulnerability","aliases":["CVE-2026-98508"],"related":[],"title":"Linux kernel: virtio GPU driver crashes on fence allocation failure","description":"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 <80> 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<TASK>\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 <48> 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</TASK>\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 <80> 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---","summary":"The virtio GPU driver in the Linux kernel does not check whether fence allocation succeeded, so a memory-pressure failure leads to a NULL pointer dereference in the execbuffer ioctl. The sources describe a kernel oops (denial of service); they do not describe code execution.","severity":"unknown","cvss":null,"epss":null,"exploited":false,"exploited_at":null,"products":[],"ecosystems":[],"tags":["infrastructure","kvm","linux-kernel","qemu","virtio-gpu","virtualization"],"not_affected_if":["bare-metal","no-virtio-gpu"],"how_to_check":"- `uname -r` and compare against the kernel release that contains the upstream fix for CVE-2026-98508\n- `lsmod | grep virtio_gpu` to see whether the virtio GPU driver is loaded\n- unknown for the exact affected version range","fix":"- Update the Linux kernel to a release that includes the upstream commit 'drm/virtio: fix NULL pointer dereference on fence allocation failure'\n- unknown for the exact fixed version number","status":"open","published_at":"2026-10-18T16:17:01+00:00","first_seen_at":"2026-10-23T21:57:15+00:00","triaged_at":"2026-10-25T05:25:26+00:00","updated_at":"2026-10-25T05:25:26+00:00","category":"infrastructure","confidence":0.6,"triage":{"at":"2026-10-25T05:25:26Z","model":"claude-haiku-5-5","output":{"fix":"- Update the Linux kernel to a release that includes the upstream commit 'drm/virtio: fix NULL pointer dereference on fence allocation failure'\n- unknown for the exact fixed version number","reach":"local","title":"Linux kernel: virtio GPU driver crashes on fence allocation failure","impact":"low","summary":"The virtio GPU driver in the Linux kernel does not check whether fence allocation succeeded, so a memory-pressure failure leads to a NULL pointer dereference in the execbuffer ioctl. The sources describe a kernel oops (denial of service); they do not describe code execution.","category":"infrastructure","nicknames":[],"who_cares":["linux-kernel","virtualization","qemu","kvm","virtio-gpu"],"confidence":0.6,"needs_auth":"yes","worst_case":"local user crashes the kernel through the GPU ioctl","analyst_note":"Check the NVD entry and the upstream kernel commit for the affected and fixed kernel versions, and confirm whether the flaw can be triggered beyond a kernel oops.","how_to_check":"- `uname -r` and compare against the kernel release that contains the upstream fix for CVE-2026-98508\n- `lsmod | grep virtio_gpu` to see whether the virtio GPU driver is loaded\n- unknown for the exact affected version range","needs_analyst":true,"not_affected_if":["no-virtio-gpu","bare-metal"],"who_is_affected":"Systems running Linux kernels with the virtio GPU DRM driver loaded, typically virtual machines using virtio-gpu under QEMU or KVM. Bare-metal hosts without virtio-gpu and systems without the driver loaded are unlikely to be exposed. The sources do not state the affected version range.","user_interaction":"no","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.000896,"input_tokens":5704,"output_tokens":652,"severity_before":"unknown"},"analyst_status":null,"analyst_note":null,"search":"'+0':219C,355C,361C,385C,398C,407C,546C '-2026':12A,15A '-98508':13A,16A '0':172C '00':230C,231C,246C,247C,248C,251C,252C,253C,254C,255C,269C,274C,275C,285C,286C,287C,420C,421C,422C,423C,424C,557C,558C,573C,574C,575C,578C,579C,580C,581C,582C,596C,601C,602C,612C,613C,614C '0000':154C,330C,333C,339C,341C,652C,655C '00000000':657C '0000000000000000':306C,317C,319C,323C,335C,500C,502C,504C,520C,633C,637C,639C,641C,645C '0000000000000001':508C '0000000000000003':496C '0000000000000005':635C '0000000000000010':484C '0000000000000012':300C,627C '000000000000003b':327C,649C '0000000000000090':304C,631C '0000000000000246':506C '0000000000350ef0':349C '0000000048d19000':347C '0000000080050033':343C '00000000c0406442':494C '00000246':481C '00002000000000c0':492C '00007effbf5e55a8':345C '00007fab471a82bd':490C '00007fab47435fa0':488C,512C '00007fab47436038':510C '00007fab480b9018':479C '00007fab480b9080':498C '00007fab480b96c0':329C,651C '00007ffe85ab0740':514C '00010216':292C,619C '0010':195C,205C,214C,337C,522C,532C,541C '0018':289C,616C '002b':478C '0033':410C '01':457C,462C,475C '02':268C,595C '03':265C,592C '04/01/2014':193C '05':233C,454C,560C '08':452C '09':229C,556C '0d':273C,600C '0f':226C,270C,417C,427C,453C,553C,597C '0x0000000000000090':167C '0x0000000000000090-0x0000000000000097':166C '0x0000000000000097':168C '0x102':313C '0x1203':315C '0x7fab471a82bd':411C '0xdffffc0000000012':153C '1':155C,170C '10':241C,280C,568C,607C '1e':428C '1f':418C '2009':190C '21':228C,555C '24':240C,279C,451C,567C,606C '295':202C,529C '2e':416C '398':211C,538C '3c':267C,594C '3d':456C '4':180C '44':239C,278C,566C,605C '48':237C,242C,249C,259C,262C,276C,430C,433C,436C,439C,455C,464C,476C,564C,569C,576C,586C,589C,603C '4c':281C,448C,450C,608C '4d':442C,445C '505':222C,549C '51':368C '583':380C,388C '597':374C '5a':234C,561C '63':393C '64':397C,404C,473C '66':415C '7.2.0':179C '73':461C '80':266C,593C '817':358C '84':419C '85':224C,227C,271C,551C,554C,598C '89':260C,282C,431C,434C,437C,440C,443C,446C,474C,587C,609C '8b':238C,277C,449C,565C,604C '8d':243C,570C '90':245C,284C,425C,572C,611C '914':364C '94':401C '9991':174C '9a':272C,599C 'address':152C 'alloc':9A,40B,90C,95C 'arch/x86/entry/syscall_64.c':392C,400C 'b0':283C,467C,610C 'b8':244C,250C,571C,577C 'bio':191C 'c1':263C,466C,590C 'c2':444C 'c3':414C,463C 'c7':465C 'c8':447C 'c9':235C,562C 'ca':441C 'call':350C 'caller':107C 'canon':151C 'check':37B,114C 'cmd':311C 'code':71B,223C,412C,550C 'comm':175C 'cpu':169C 'cr0':342C 'cr2':344C 'cr3':346C 'cr4':348C 'crash':6A 'creat':130C,200C,527C 'cs':336C 'ctrl':312C 'cve':11A,14A 'd6':438C 'd8':472C 'denial':64B 'deref':163C 'derefer':53B,87C,133C 'describ':60B,70B 'df':258C,585C 'dffffc0000000000':294C,621C 'driver':5A,30B,140C 'drivers/gpu/drm/drm_ioctl.c':357C,363C 'drivers/gpu/drm/virtio/virtgpu_submit.c':201C,210C,221C,528C,537C,548C 'drm':352C,359C 'drm/virtio':83C 'ds':338C 'due':98C 'e8':232C,559C 'ea':264C,591C 'ed':225C,552C 'eflag':291C,480C,618C 'end':518C 'entri':402C 'error':314C 'es':340C 'event':129C,199C,526C 'execbuff':56B,217C,544C 'execut':72B 'f0':458C 'f3':426C 'f7':435C,471C 'f8':432C 'fa':261C,429C,588C 'fail':97C 'failur':10A,47B,91C 'fault':146C 'fb':236C,563C 'fc':256C,583C 'fenc':8A,39B,89C,94C,124C,128C,198C,525C 'ff':257C,413C,459C,460C,468C,469C,470C,584C 'ffff8880132c4000':321C,643C 'ffff888073b6c700':325C,647C 'ffff888098ae9000':654C 'ffff8880eb6e9000':332C 'ffffc900039dfad0':290C,617C 'ffffc900039dfdd8':296C,623C 'ffffffff85f6fd3d':298C,625C 'ffffffff85f6fd4b':302C,629C 'ffffffffffffffda':486C 'fix':84C 'follow':78C 'found':135C 'fs':328C,650C 'fs/ioctl.c':367C,373C,379C,387C 'full':182C 'fuzz':137C 'general':144C 'gpu':4A,25B,29B,93C,110C,118C,127C,197C,207C,216C,308C,524C,534C,543C 'gs':331C,653C 'hardwar':183C 'hwframe':406C 'ich9':189C 'infrastructur':17B 'init':111C,119C,208C,535C 'inlin':203C,212C,369C,375C,381C,394C,530C,539C 'ioctl':57B,218C,353C,360C,366C,372C,378C,384C,545C 'kasan':157C,159C 'kernel':2A,21B,34B,62B,76C,354C 'knlgs':334C,656C 'kvm':18B 'later':116C 'lead':48B 'like':108C 'link':516C 'linux':1A,20B,33B,75C 'linux-kernel':19B 'memori':45B,100C 'memory-pressur':44B 'modul':515C 'name':184C 'never':113C 'non':150C 'non-canon':149C 'nopti':158C 'null':51B,85C,104C,123C,161C 'null-ptr-deref':160C 'oop':63B,143C 'orig':482C 'pass':121C 'pc':187C 'pid':173C 'pointer':52B,86C 'preempt':181C 'pressur':46B,101C 'probabl':147C 'process':310C 'protect':145C 'ptr':162C 'q35':188C 'qemu':22B,185C 'r08':499C,634C 'r09':501C,636C 'r0virtio':307C 'r10':316C,503C,638C 'r11':318C,505C,640C 'r12':320C,507C,642C 'r13':322C,509C,644C 'r14':324C,511C,646C 'r15':326C,513C,648C 'rang':165C 'rax':293C,483C,485C,620C 'rbp':305C,497C,632C 'rbx':295C,487C,622C 'rcx':297C,489C,624C 'rdi':303C,495C,630C 'rdx':299C,491C,626C 'rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org':192C 'resolv':82C 'return':103C 'rip':194C,204C,213C,409C,521C,531C,540C 'rsi':301C,493C,628C 'rsp':288C,477C,615C 'se':376C 'servic':66B 'smp':156C 'sourc':59B 'standard':186C 'submit':112C,120C,209C,536C 'succeed':41B 'sys':371C,377C,383C 'syscal':390C,396C,403C 'syz.0.121':176C 'syzkal':142C 'taint':178C 'trace':351C,519C 'truncat':658C 'uid':171C 'uncondit':132C 'vfs':365C 'virgl':309C 'virtio':3A,24B,28B,92C,109C,117C,126C,139C,196C,206C,215C,523C,533C,542C 'virtio-gpu':23B 'virtual':26B 'vulner':79C 'whether':38B 'x116/0x800':399C 'x18e/0x210':386C 'x1f4/0x3e0':356C 'x5f4/0xc70':362C 'x64':382C,391C 'x77/0x7f':408C 'xc78/0x1aa0':220C,547C","nicknames":[],"mitigations":[],"who_affected":"Systems running Linux kernels with the virtio GPU DRM driver loaded, typically virtual machines using virtio-gpu under QEMU or KVM. Bare-metal hosts without virtio-gpu and systems without the driver loaded are unlikely to be exposed. The sources do not state the affected version range.","tier":"C","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-10-18T16:17:01+00:00","kev":null,"cvss_vector":null,"cvss_by":null,"poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-98508","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98508","severity":null,"published_at":"2026-10-18T16:17:01+00:00","modified_at":"2026-10-19T10:19:04+00:00","first_seen_at":"2026-10-23T21:57:15+00:00","fetched_at":"2026-10-23T22:28:56+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}