Cloudanix VulnDB

CVE-2026-98511

None

CVSS

—

EPSS

0.2%

Published

Oct 18, 2026

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A flaw in the Linux driver for certain NVIDIA graphics cards can cause unexpected warnings or instability when graphics memory operations fail in specific ways.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Denial Of Service
Component
OS kernel
Class
Other
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Incorrect handling of pin counts in nouveau_bo_pin_locked allows an extra ttm_bo_pin call on domain mismatch failure, leaving an unmatched pin that triggers WARN_ON_ONCE in ttm_bo_release during object cleanup.

Why it matters to the business

Systems using the nouveau driver may experience kernel warnings, unexpected GPU object release behavior, or instability during graphics operations, increasing operational risk on affected Linux kernels.

How an attack unfolds

An attacker with local access crafts GPU buffer operations that cause a pin domain incompatibility in nouveau_bo_pin_locked, triggering the extra pin without a matching unpin; repeated triggers via userspace DRM calls can surface the warning and potential resource accounting issues.

How to fix it

Update the Linux kernel to a version containing the fix for the pin count handling in nouveau_bo_pin_locked; apply vendor-supplied kernel packages as soon as available.

How to confirm the fix worked

Confirm the patched kernel is running, then exercise nouveau pin/unpin paths with test workloads and verify absence of the ttm_bo_release warning; review kernel changelog for the commit message referencing nouveau_bo_pin_locked.

Typical attack path

  1. Obtain local unprivileged access on a Linux system with nouveau loaded
  2. Open a DRM file descriptor and perform GEM buffer allocation
  3. Issue pin requests with incompatible memory domains to hit the failure path
  4. Trigger object deletion to reach ttm_bo_release and observe the warning
  5. Repeat to amplify effects on GPU resource accounting

How to detect it

Search kernel logs for ttm_bo_release warnings mentioning pin_count, nouveau driver messages, and Syzkaller-style GPU handle errors; correlate with processes performing DRM GEM operations around the time of the warning.

What your security team should do

  • Prioritize kernel updates on systems using the nouveau driver within normal patch windows
  • Monitor kernel logs for ttm_bo_release warnings on GPU-equipped hosts
  • Limit unprivileged local access where possible until patched kernels are deployed

The record

In the Linux kernel, the following vulnerability has been resolved: drm/nouveau: don't bump pin count on failed re-pin in nouveau_bo_pin_locked() nouveau_bo_pin_locked() checks whether an already pinned BO is in a memory domain compatible with a new pin request. When the domains are incompatible, it sets -EBUSY but still calls ttm_bo_pin() before returning. Callers treat a failed nouveau_bo_pin() as not having acquired a new pin, so the extra pin count is never decreased by a matching unpin. This triggers the warning in ttm_bo_release(): WARN_ON_ONCE(bo->pin_count); Found when fuzzing the nouveau driver with a modified Syzkaller: WARNING: drivers/gpu/drm/ttm/ttm_bo.c:256 at ttm_bo_release+0x827/0x9e0 drivers/gpu/drm/ttm/ttm_bo.c:256, CPU#1: syz.3.24/2212 Modules linked in: CPU: 1 UID: 0 PID: 2212 Comm: syz.3.24 Not tainted 7.2.0 #24 PREEMPT(lazy) nouveau 0000:01:00.0: gsp:msg fn:103 len:0x40/0x20 res:0x19 resp:0x19 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:ttm_bo_release+0x827/0x9e0 drivers/gpu/drm/ttm/ttm_bo.c:256 Code: 02 00 0f 85 51 01 00 00 48 8b 7b 08 e8 d2 20 01 00 e9 80 fd ff ff e8 d8 15 c0 fe 90 0f 0b 90 e9 e1 f8 ff ff e8 ca 15 c0 fe 90 <0f> 0b 90 e9 a4 f8 ff ff e8 bc 15 c0 fe be 03 00 00 00 4c 89 e7 e8 msg: 00000000: 05 00 d0 c1 04 00 f0 f1 01 30 00 00 2d 90 00 00 .........0..-... RSP: 0018:ffffc9000f5cf710 EFLAGS: 00010293 RAX: 0000000000000000 RBX: ffff888018e5d2a8 RCX: ffffffff82bb1b36 RDX: ffff888017b68000 RSI: 0000000000000004 RDI: ffff888018e5d2a8 msg: 00000010: 19 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ RBP: ffff88801261c720 R08: 0000000000000001 R09: ffffed10031cba55 R10: ffff888018e5d2ab R11: 00000000000000f3 R12: ffff888018e5d290 R13: ffff888018e5d2d4 R14: ffff88801b219c18 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880e0f6f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b31223ffc CR3: 0000000028e00005 CR4: 0000000000770ef0 PKRU: 80000000 Call Trace: <TASK> kref_put include/linux/kref.h:65 [inline] ttm_bo_put drivers/gpu/drm/ttm/ttm_bo.c:325 [inline] ttm_bo_fini+0x55/0x80 drivers/gpu/drm/ttm/ttm_bo.c:330 nouveau_gem_object_del+0xb2/0x1b0 drivers/gpu/drm/nouveau/nouveau_gem.c:90 drm_gem_object_free+0x5f/0x90 drivers/gpu/drm/drm_gem.c:1165 kref_put include/linux/kref.h:65 [inline] __drm_gem_object_put include/drm/drm_gem.h:562 [inline] drm_gem_object_put include/drm/drm_gem.h:575 [inline] nouveau_abi16_chan_fini.constprop.0+0x44f/0x5a0 drivers/gpu/drm/nouveau/nouveau_abi16.c:195 nouveau 0000:01:00.0: syz.2.23[2209]: Unknown handle 0x00000000 nouveau_abi16_fini+0x1d0/0x340 drivers/gpu/drm/nouveau/nouveau_abi16.c:225 nouveau_drm_postclose+0x18b/0x3e0 drivers/gpu/drm/nouveau/nouveau_drm.c:1284 nouveau 0000:01:00.0: syz.2.23[2209]: validate_init drm_file_free.part.0+0x6d6/0xb60 drivers/gpu/drm/drm_file.c:267 drm_file_free drivers/gpu/drm/drm_file.c:237 [inline] drm_close_helper.isra.0+0x11a/0x160 drivers/gpu/drm/drm_file.c:290 drm_release+0x1ab/0x330 drivers/gpu/drm/drm_file.c:438 __fput+0x39c/0xa60 fs/file_table.c:512 nouveau 0000:01:00.0: syz.2.23[2209]: validate: -2 task_work_run+0x15a/0x230 kernel/task_work.c:233 exit_task_work include/linux/task_work.h:40 [inline] do_exit+0x82b/0x25a0 kernel/exit.c:1009 do_group_exit+0xc2/0x280 kernel/exit.c:1152 get_signal+0x1d6e/0x1f30 kernel/signal.c:3046 arch_do_signal_or_restart+0x7d/0x6e0 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop+0xdf/0x440 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline] do_syscall_64+0x4f8/0x690 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RI ---truncated---

Affected packages

Ecosystem Package Introduced Fixed