{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43497", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:56.013Z", "datePublished": "2026-05-21T12:12:47.150Z", "dateUpdated": "2026-08-05T12:28:19.915Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:28:19.915Z" }, "descriptions": [ { "lang": "en", "value": "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." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.3, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The entire exploit is driven by local syscalls (open/mmap/FBIOPUT_VSCREENINFO/close) on the /dev/fbN character device; the attacker is a local software user, not a malicious USB device feeding crafted data, so the vector to the vulnerable component is local rather than physical.\nAC:L - The attacker reliably performs the mmap + realloc-via-ioctl + close sequence and can detect the disconnect before closing; the freed-page mapping is then deterministic with no race or uncontrolled memory-layout condition required to trigger the UAF.\nPR:L - Exploitation requires read/write access to the framebuffer device node, which is available to an ordinary logged-in/video-group user (or kiosk app user) but not to a fully unprivileged unauthenticated actor.\nUI:R - The freeing vfree only runs after a USB disconnect (unregister_framebuffer), so completing the exploit depends on a disconnect event (undock/unplug) performed by the user or environment rather than by the attacker's own code.\nS:U - The use-after-free corrupts kernel memory within the same security authority (the kernel); there is no VM, IOMMU, or sandbox boundary crossed.\nC:H - The process keeps a read mapping to freed pages that are recycled for arbitrary kernel allocations, allowing disclosure of arbitrary kernel memory.\nI:H - The same mapping retains write access to the freed pages once reused by other kernel objects, providing an arbitrary-write primitive suitable for privilege escalation or control-flow hijack.\nA:H - A use-after-free of freed kernel pages readily causes memory corruption and a kernel panic/oops." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/video/fbdev/udlfb.c", "include/video/udlfb.h" ], "versions": [ { "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd", "lessThan": "60f711cfd580f86fea8284146ac133804e728f9a", "status": "affected", "versionType": "git" }, { "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd", "lessThan": "5931f5651ee32bd41b3323256b31fcc8e71336ed", "status": "affected", "versionType": "git" }, { "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd", "lessThan": "e3d9865dacd7435b8465848428210d0f0c673311", "status": "affected", "versionType": "git" }, { "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd", "lessThan": "4f312c30f0368e8d2a76aa650dff73f23490b5e7", "status": "affected", "versionType": "git" }, { "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd", "lessThan": "18dd358de72d57993422cbb5dfb29ccd74efe192", "status": "affected", "versionType": "git" }, { "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd", "lessThan": "da9b065cedfd3b574f229d5be594e6aa47a27ae6", "status": "affected", "versionType": "git" }, { "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd", "lessThan": "a2c53a3822ee26e8d758071815b9ed3bf6669fc1", "status": "affected", "versionType": "git" }, { "version": "7433914efd584b22bb49d3e1eee001f5d0525ecd", "lessThan": "8de779dc40d35d39fa07387b6f921eb11df0f511", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/video/fbdev/udlfb.c", "include/video/udlfb.h" ], "versions": [ { "version": "4.19", "status": "affected" }, { "version": "0", "lessThan": "4.19", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.258", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.209", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.175", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.140", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.88", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.30", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0.7", "lessThanOrEqual": "7.0.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "5.10.258" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "5.15.209" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.1.175" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.6.140" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.12.88" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "6.18.30" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "7.0.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19", "versionEndExcluding": "7.1" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/60f711cfd580f86fea8284146ac133804e728f9a" }, { "url": "https://git.kernel.org/stable/c/5931f5651ee32bd41b3323256b31fcc8e71336ed" }, { "url": "https://git.kernel.org/stable/c/e3d9865dacd7435b8465848428210d0f0c673311" }, { "url": "https://git.kernel.org/stable/c/4f312c30f0368e8d2a76aa650dff73f23490b5e7" }, { "url": "https://git.kernel.org/stable/c/18dd358de72d57993422cbb5dfb29ccd74efe192" }, { "url": "https://git.kernel.org/stable/c/da9b065cedfd3b574f229d5be594e6aa47a27ae6" }, { "url": "https://git.kernel.org/stable/c/a2c53a3822ee26e8d758071815b9ed3bf6669fc1" }, { "url": "https://git.kernel.org/stable/c/8de779dc40d35d39fa07387b6f921eb11df0f511" } ], "title": "fbdev: udlfb: add vm_ops to dlfb_ops_mmap to prevent use-after-free", "x_generator": { "engine": "bippy-1.2.0" } } } }