{"id":"CVE-2026-53401","summary":"fbdev: omap2: fix use-after-free in omapfb_mmap","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nfbdev: omap2: fix use-after-free in omapfb_mmap\n\nomapfb_mmap() has a race condition with OMAPFB_SETUP_PLANE ioctl that\ncan lead to use-after-free:\n\nThe fb_mmap() entry point holds mm_lock but not lock (fb_info-\u003elock),\nwhile ioctl handlers like OMAPFB_SETUP_PLANE hold lock but not mm_lock.\nThis allows concurrent execution.\n\nIn omapfb_mmap():\n1. rg = omapfb_get_mem_region(ofbi-\u003eregion);      // Get old region ref\n2. start = omapfb_get_region_paddr(ofbi);          // Read from NEW region\n3. len = fix-\u003esmem_len;                             // Read from NEW region\n4. vm_iomap_memory(vma, start, len);               // Map NEW region memory\n5. atomic_inc(&rg-\u003emap_count);                      // Increment OLD region!\n\nConcurrently, OMAPFB_SETUP_PLANE can:\n- Reassign ofbi-\u003eregion = new_rg\n- Update fix-\u003esmem_len\n- OMAPFB_SETUP_MEM then checks NEW region's map_count (0!) and frees it\n\nThis leaves userspace with a mapping to freed physical memory.\n\nThe fix is to read all required values (start, len) from the same\nregion reference (rg) that will have its map_count incremented,\npreventing the region from being freed while still mapped.","modified":"2026-07-22T05:29:52.466703865Z","published":"2026-07-19T12:02:01.209Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53401.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6eb6ebcc8590007ad59ddccc8b5f9201655b33f8"},{"type":"WEB","url":"https://git.kernel.org/stable/c/7958e67375aa111522086286bba13cfc0816ce8d"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53401.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53401"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"078ff546a806b2c2ab74c25c8edd4c6d4680656a"},{"fixed":"6eb6ebcc8590007ad59ddccc8b5f9201655b33f8"},{"fixed":"7958e67375aa111522086286bba13cfc0816ce8d"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53401.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.36"},{"fixed":"7.1.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53401.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}]}