# CVE-2025-40037: fbdev: simplefb: Fix use after free in simplefb_detach_genpds() > A use-after-free vulnerability in the Linux kernel's simplefb driver allows local attackers to cause a system crash or potentially execute arbitrary code. - **Severity:** Not scored - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 28 Oct 2025 - **Updated:** 11 May 2026 - **Also known as:** BELL-CVE-2025-40037, DEBIAN-CVE-2025-40037, GHSA-5hpm-4x7m-g857, ROOT-OS-DEBIAN-13-CVE-2025-40037, ROOT-OS-UBUNTU-2404-CVE-2025-40037, UBUNTU-CVE-2025-40037 ## What is CVE-2025-40037? CVE-2025-40037 is an use after free vulnerability in Linux, published on 28 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description In the Linux kernel, the following vulnerability has been resolved: fbdev: simplefb: Fix use after free in simplefb_detach_genpds() The pm_domain cleanup can not be devres managed as it uses struct simplefb_par which is allocated within struct fb_info by framebuffer_alloc(). This allocation is explicitly freed by unregister_framebuffer() in simplefb_remove(). Devres managed cleanup runs after the device remove call and thus can no longer access struct simplefb_par. Call simplefb_detach_genpds() explicitly from simplefb_destroy() like the cleanup functions for clocks and regulators. Fixes an use after free on M2 Mac mini during aperture_remove_conflicting_devices() using the downstream asahi kernel with Debian's kernel config. For unknown reasons this started to consistently dereference an invalid pointer in v6.16.3 based kernels. [ 6.736134] BUG: KASAN: slab-use-after-free in simplefb_detach_genpds+0x58/0x220 [ 6.743545] Read of size 4 at addr ffff8000304743f0 by task (udev-worker)/227 [ 6.750697] [ 6.752182] CPU: 6 UID: 0 PID: 227 Comm: (udev-worker) Tainted: G S 6.16.3-asahi+ #16 PREEMPTLAZY [ 6.752186] Tainted: [S]=CPU_OUT_OF_SPEC [ 6.752187] Hardware name: Apple Mac mini (M2, 2023) (DT) [ 6.752189] Call trace: [ 6.752190] show_stack+0x34/0x98 (C) [ 6.752194] dump_stack_lvl+0x60/0x80 [ 6.752197] print_report+0x17c/0x4d8 [ 6.752201] kasan_report+0xb4/0x100 [ 6.752206] __asan_report_load4_noabort+0x20/0x30 [ 6.752209] simplefb_detach_genpds+0x58/0x220 [ 6.752213] devm_action_release+0x50/0x98 [ 6.752216] release_nodes+0xd0/0x2c8 [ 6.752219] devres_release_all+0xfc/0x178 [ 6.752221] device_unbind_cleanup+0x28/0x168 [ 6.752224] device_release_driver_internal+0x34c/0x470 [ 6.752228] device_release_driver+0x20/0x38 [ 6.752231] bus_remove_device+0x1b0/0x380 [ 6.752234] device_del+0x314/0x820 [ 6.752238] platform_device_del+0x3c/0x1e8 [ 6.752242] platform_device_unregister+0x20/0x50 [ 6.752246] aperture_detach_platform_device+0x1c/0x30 [ 6.752250] aperture_detach_devices+0x16c/0x290 [ 6.752253] aperture_remove_conflicting_devices+0x34/0x50 ... [ 6.752343] [ 6.967409] Allocated by task 62: [ 6.970724] kasan_save_stack+0x3c/0x70 [ 6.974560] kasan_save_track+0x20/0x40 [ 6.978397] kasan_save_alloc_info+0x40/0x58 [ 6.982670] __kasan_kmalloc+0xd4/0xd8 [ 6.986420] __kmalloc_noprof+0x194/0x540 [ 6.990432] framebuffer_alloc+0xc8/0x130 [ 6.994444] simplefb_probe+0x258/0x2378 ... [ 7.054356] [ 7.055838] Freed by task 227: [ 7.058891] kasan_save_stack+0x3c/0x70 [ 7.062727] kasan_save_track+0x20/0x40 [ 7.066565] kasan_save_free_info+0x4c/0x80 [ 7.070751] __kasan_slab_free+0x6c/0xa0 [ 7.074675] kfree+0x10c/0x380 [ 7.077727] framebuffer_release+0x5c/0x90 [ 7.081826] simplefb_destroy+0x1b4/0x2c0 [ 7.085837] put_fb_info+0x98/0x100 [ 7.089326] unregister_framebuffer+0x178/0x320 [ 7.093861] simplefb_remove+0x3c/0x60 [ 7.097611] platform_remove+0x60/0x98 [ 7.101361] device_remove+0xb8/0x160 [ 7.105024] device_release_driver_internal+0x2fc/0x470 [ 7.110256] device_release_driver+0x20/0x38 [ 7.114529] bus_remove_device+0x1b0/0x380 [ 7.118628] device_del+0x314/0x820 [ 7.122116] platform_device_del+0x3c/0x1e8 [ 7.126302] platform_device_unregister+0x20/0x50 [ 7.131012] aperture_detach_platform_device+0x1c/0x30 [ 7.136157] aperture_detach_devices+0x16c/0x290 [ 7.140779] aperture_remove_conflicting_devices+0x34/0x50 ... ## Which versions are affected by CVE-2025-40037? ## How do I fix CVE-2025-40037? Apply the vendor's patch. ## Is CVE-2025-40037 being exploited? There is no known exploitation of CVE-2025-40037 in the wild and no public exploit code. ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2025-40037 and fix it if it is affected. What it is: CVE-2025-40037 is an use after free vulnerability in Linux, published on 28 Oct 2025. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2025-40037 in the wild and no public exploit code. Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2025-40037/ (Markdown: https://insights.sbomify.com/CVE-2025-40037/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40037 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40037 - OSV: https://osv.dev/vulnerability/CVE-2025-40037 --- From sbomify Insights: https://insights.sbomify.com/CVE-2025-40037/ Summaries are generated and may contain mistakes; the official description above is the record.