fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free_CVE-2026-43497

{
    "lastseen": "",
    "description": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free\n\ndlfb_ops_mmap() uses remap_pfn_range() to map vmalloc framebuffer pages\nto userspace but sets no vm_ops on the VMA. This means the kernel cannot\ntrack active mmaps. When dlfb_realloc_framebuffer() replaces the backing\nbuffer via FBIOPUT_VSCREENINFO, existing mmap PTEs are not invalidated.\nOn USB disconnect, dlfb_ops_destroy() calls vfree() on the old pages\nwhile userspace PTEs still reference them, resulting in a use-after-free:\nthe process retains read/write access to freed kernel pages.\n\nAdd vm_operations_struct with open/close callbacks that maintain an\natomic mmap_count on struct dlfb_data. In dlfb_realloc_framebuffer(),\ncheck mmap_count and return -EBUSY if the buffer is currently mapped,\npreventing buffer replacement while userspace holds stale PTEs.\n\nTested with PoC using dummy_hcd + raw_gadget USB device emulation.",
    "published": "2026-05-21T12:12:47.150Z",
    "modified": "2026-05-30T10:45:14.782Z",
    "type": "cve",
    "title": "fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free",
    "source": "Linux",
    "references": "https://git.kernel.org/stable/c/4f312c30f0368e8d2a76aa650dff73f23490b5e7\nhttps://git.kernel.org/stable/c/18dd358de72d57993422cbb5dfb29ccd74efe192\nhttps://git.kernel.org/stable/c/da9b065cedfd3b574f229d5be594e6aa47a27ae6\nhttps://git.kernel.org/stable/c/a2c53a3822ee26e8d758071815b9ed3bf6669fc1\nhttps://git.kernel.org/stable/c/8de779dc40d35d39fa07387b6f921eb11df0f511",
    "id": "CVE-2026-43497",
    "bulletinFamily": "",
    "cwe": null,
    "cvelist": null,
    "sourceData": "Linux Linux 7433914efd584b22bb49d3e1eee001f5d0525ecd\nLinux Linux 7433914efd584b22bb49d3e1eee001f5d0525ecd\nLinux Linux 7433914efd584b22bb49d3e1eee001f5d0525ecd\nLinux Linux 7433914efd584b22bb49d3e1eee001f5d0525ecd\nLinux Linux 7433914efd584b22bb49d3e1eee001f5d0525ecd\nLinux Linux 4.19",
    "sourceHref": "",
    "cvss": {
        "score": 7.3,
        "severity": "HIGH",
        "vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H",
        "version": "3.1"
    },
    "cvss2": [],
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        "baseScore": 0,
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        "privilegesRequired": "",
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        "scope": "",
        "confidentialityImpact": "",
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        "availabilityImpact": "",
        "cvssV3": {
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    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Linux",
    "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd",
    "vendor": "Linux",
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    "ai_score": 0
}