GHSA-82RJ-6XVQ-73V7

Vulnerability from github – Published: 2026-10-18 18:31 – Updated: 2026-10-24 15:32
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

drm/nouveau: fix double-free in nvif_vmm_dtor

On failure, nouveau_cli_init() calls nouveau_cli_fini() to tear the client down. Then, nouveau_drm_open() also enters into its cleanup path and calls nouveau_cli_fini() AGAIN. nouveau_cli_fini() calls nouveau_vmm_fini():

void
nouveau_vmm_fini(struct nouveau_vmm *vmm)
{
    nouveau_svmm_fini(&vmm->svmm);
    nvif_vmm_dtor(&vmm->vmm);
    vmm->cli = NULL;
}

Inside nvif_vmm_dtor(), vmm->page is freed unconditionally:

void
nvif_vmm_dtor(struct nvif_vmm *vmm)
{
    kfree(vmm->page);
    nvif_object_dtor(&vmm->object);
}

vmm->page is never cleared after being freed, so the second call of nvif_vmm_dtor() will cause a double-free.

Found by fuzzing the nouveau driver with a modified Syzkaller:

BUG: KASAN: double-free in nvif_vmm_dtor+0x31/0x50 drivers/gpu/drm/nouveau/nvif/vmm.c:194
Free of addr ffff888010fcdc30 by task syz.0.173/2567

CPU: 1 UID: 0 PID: 2567 Comm: syz.0.173 Not tainted 7.2.0 #24 PREEMPT(lazy)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x95/0xe0 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xcb/0x5a0 mm/kasan/report.c:482
kasan_report_invalid_free+0xaa/0xd0 mm/kasan/report.c:557
check_slab_allocation+0xe4/0x110 mm/kasan/common.c:235
kasan_slab_pre_free include/linux/kasan.h:199 [inline]
slab_free_hook mm/slub.c:2622 [inline]
slab_free mm/slub.c:6377 [inline]
kfree+0x192/0x590 mm/slub.c:6692
nvif_vmm_dtor+0x31/0x50 drivers/gpu/drm/nouveau/nvif/vmm.c:194
nouveau_vmm_fini+0x16/0x50 drivers/gpu/drm/nouveau/nouveau_vmm.c:127
nouveau_cli_fini+0x10e/0x210 drivers/gpu/drm/nouveau/nouveau_drm.c:225
nouveau_drm_open+0x24e/0x740 drivers/gpu/drm/nouveau/nouveau_drm.c:1255
drm_file_alloc+0x5f2/0xad0 drivers/gpu/drm/drm_file.c:176
drm_open_helper+0x1d7/0x4a0 drivers/gpu/drm/drm_file.c:335
drm_open+0x190/0x3d0 drivers/gpu/drm/drm_file.c:388
drm_stub_open+0x1f2/0x460 drivers/gpu/drm/drm_drv.c:1211
chrdev_open+0x21c/0x660 fs/char_dev.c:411
do_dentry_open+0x59d/0x12b0 fs/open.c:947
vfs_open+0x82/0x390 fs/open.c:1052
do_open fs/namei.c:4700 [inline]
path_openat+0x2345/0x3420 fs/namei.c:4863
do_file_open+0x207/0x460 fs/namei.c:4892
do_sys_openat2+0xd1/0x1d0 fs/open.c:1368
do_sys_open fs/open.c:1374 [inline]
__do_sys_openat fs/open.c:1390 [inline]
__se_sys_openat fs/open.c:1385 [inline]
__x64_sys_openat+0x144/0x200 fs/open.c:1385
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x690 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc6d687594d
Code: 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
RSP: 002b:00007fc6d5295008 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fc6d6b06180 RCX: 00007fc6d687594d
RDX: 0000000000022501 RSI: 0000200000000000 RDI: ffffffffffffff9c
RBP: 00007fc6d691c303 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc6d6b06218 R14: 00007fc6d6b06180 R15: 00007ffd9451d760
</TASK>

Allocated by task 2567 on cpu 1 at 163.593900s:
kasan_save_stack+0x24/0x50 mm/kasan/common.c:57
kasan_save_track+0x17/0x60 mm/kasan/common.c:78
poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415
kasan_kmalloc include/linux/kasan.h:263 [inline]
__do_kmalloc_node mm/slub.c:5334 [inline]
__kmalloc_noprof+0x304/0x7c0 mm/slub.c:5359
_kmalloc_noprof include/linux/slab.h:992 [inline]
nvif_vmm_ctor+0x3c0/0x7e0 drivers/gpu/drm/nouveau/nvif/vmm.c:237
nouveau_vmm_init+0x40/0x90 drivers/gpu/drm/nouveau/nouveau_vmm.c:134
nouveau_cli_init+0x7b9/0

---truncated---

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Show details on source website
To clipboard 

{
  "affected": [],
  "aliases": [
    "CVE-2026-98515"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-18T16:17:02Z",
    "severity": "HIGH"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/nouveau: fix double-free in nvif_vmm_dtor\n\nOn failure, nouveau_cli_init() calls nouveau_cli_fini() to tear\nthe client down. Then, nouveau_drm_open() also enters into its\ncleanup path and calls nouveau_cli_fini() AGAIN. nouveau_cli_fini()\ncalls nouveau_vmm_fini():\n\n\tvoid\n\tnouveau_vmm_fini(struct nouveau_vmm *vmm)\n\t{\n\t\tnouveau_svmm_fini(\u0026vmm-\u003esvmm);\n\t\tnvif_vmm_dtor(\u0026vmm-\u003evmm);\n\t\tvmm-\u003ecli = NULL;\n\t}\n\nInside nvif_vmm_dtor(), vmm-\u003epage is freed unconditionally:\n\n\tvoid\n\tnvif_vmm_dtor(struct nvif_vmm *vmm)\n\t{\n\t\tkfree(vmm-\u003epage);\n\t\tnvif_object_dtor(\u0026vmm-\u003eobject);\n\t}\n\nvmm-\u003epage is never cleared after being freed, so the second call of\nnvif_vmm_dtor() will cause a double-free.\n\nFound by fuzzing the nouveau driver with a modified Syzkaller:\n\n\tBUG: KASAN: double-free in nvif_vmm_dtor+0x31/0x50 drivers/gpu/drm/nouveau/nvif/vmm.c:194\n\tFree of addr ffff888010fcdc30 by task syz.0.173/2567\n\n\tCPU: 1 UID: 0 PID: 2567 Comm: syz.0.173 Not tainted 7.2.0 #24 PREEMPT(lazy)\n\tHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n\tCall Trace:\n\t\u003cTASK\u003e\n\t__dump_stack lib/dump_stack.c:94 [inline]\n\tdump_stack_lvl+0x95/0xe0 lib/dump_stack.c:120\n\tprint_address_description mm/kasan/report.c:378 [inline]\n\tprint_report+0xcb/0x5a0 mm/kasan/report.c:482\n\tkasan_report_invalid_free+0xaa/0xd0 mm/kasan/report.c:557\n\tcheck_slab_allocation+0xe4/0x110 mm/kasan/common.c:235\n\tkasan_slab_pre_free include/linux/kasan.h:199 [inline]\n\tslab_free_hook mm/slub.c:2622 [inline]\n\tslab_free mm/slub.c:6377 [inline]\n\tkfree+0x192/0x590 mm/slub.c:6692\n\tnvif_vmm_dtor+0x31/0x50 drivers/gpu/drm/nouveau/nvif/vmm.c:194\n\tnouveau_vmm_fini+0x16/0x50 drivers/gpu/drm/nouveau/nouveau_vmm.c:127\n\tnouveau_cli_fini+0x10e/0x210 drivers/gpu/drm/nouveau/nouveau_drm.c:225\n\tnouveau_drm_open+0x24e/0x740 drivers/gpu/drm/nouveau/nouveau_drm.c:1255\n\tdrm_file_alloc+0x5f2/0xad0 drivers/gpu/drm/drm_file.c:176\n\tdrm_open_helper+0x1d7/0x4a0 drivers/gpu/drm/drm_file.c:335\n\tdrm_open+0x190/0x3d0 drivers/gpu/drm/drm_file.c:388\n\tdrm_stub_open+0x1f2/0x460 drivers/gpu/drm/drm_drv.c:1211\n\tchrdev_open+0x21c/0x660 fs/char_dev.c:411\n\tdo_dentry_open+0x59d/0x12b0 fs/open.c:947\n\tvfs_open+0x82/0x390 fs/open.c:1052\n\tdo_open fs/namei.c:4700 [inline]\n\tpath_openat+0x2345/0x3420 fs/namei.c:4863\n\tdo_file_open+0x207/0x460 fs/namei.c:4892\n\tdo_sys_openat2+0xd1/0x1d0 fs/open.c:1368\n\tdo_sys_open fs/open.c:1374 [inline]\n\t__do_sys_openat fs/open.c:1390 [inline]\n\t__se_sys_openat fs/open.c:1385 [inline]\n\t__x64_sys_openat+0x144/0x200 fs/open.c:1385\n\tdo_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n\tdo_syscall_64+0x115/0x690 arch/x86/entry/syscall_64.c:94\n\tentry_SYSCALL_64_after_hwframe+0x77/0x7f\n\tRIP: 0033:0x7fc6d687594d\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:00007fc6d5295008 EFLAGS: 00000246 ORIG_RAX: 0000000000000101\n\tRAX: ffffffffffffffda RBX: 00007fc6d6b06180 RCX: 00007fc6d687594d\n\tRDX: 0000000000022501 RSI: 0000200000000000 RDI: ffffffffffffff9c\n\tRBP: 00007fc6d691c303 R08: 0000000000000000 R09: 0000000000000000\n\tR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\n\tR13: 00007fc6d6b06218 R14: 00007fc6d6b06180 R15: 00007ffd9451d760\n\t\u003c/TASK\u003e\n\n\tAllocated by task 2567 on cpu 1 at 163.593900s:\n\tkasan_save_stack+0x24/0x50 mm/kasan/common.c:57\n\tkasan_save_track+0x17/0x60 mm/kasan/common.c:78\n\tpoison_kmalloc_redzone mm/kasan/common.c:398 [inline]\n\t__kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:415\n\tkasan_kmalloc include/linux/kasan.h:263 [inline]\n\t__do_kmalloc_node mm/slub.c:5334 [inline]\n\t__kmalloc_noprof+0x304/0x7c0 mm/slub.c:5359\n\t_kmalloc_noprof include/linux/slab.h:992 [inline]\n\tnvif_vmm_ctor+0x3c0/0x7e0 drivers/gpu/drm/nouveau/nvif/vmm.c:237\n\tnouveau_vmm_init+0x40/0x90 drivers/gpu/drm/nouveau/nouveau_vmm.c:134\n\tnouveau_cli_init+0x7b9/0\n---truncated---",
  "id": "GHSA-82rj-6xvq-73v7",
  "modified": "2026-10-24T15:32:47Z",
  "published": "2026-10-18T18:31:52Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98515"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/023e7a01f8fb27799f0987b5bcda325d73a2904c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/109a8d2d5b7d2719ebe09df3f9241023900b3846"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/279e5ac137370e274a09dd552547ae6bddd0d4d5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/375901ac0f286e81be00a4126e57d488cb401884"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/872a5473c02a26c955be44d52b7ab2f8ea70a2cf"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/97077ac87afe9e91ec074ef0be64454e7ccbf344"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bf542ecd4f60d4689818d194e7ca74772fe0f8b5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f09f4a536935b15539f2de9fe775a2641202be90"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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