{"id":"CVE-2026-31654","summary":"mm/vma: fix memory leak in __mmap_region()","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nmm/vma: fix memory leak in __mmap_region()\n\ncommit 605f6586ecf7 (\"mm/vma: do not leak memory when .mmap_prepare\nswaps the file\") handled the success path by skipping get_file() via\nfile_doesnt_need_get, but missed the error path.\n\nWhen /dev/zero is mmap'd with MAP_SHARED, mmap_zero_prepare() calls\nshmem_zero_setup_desc() which allocates a new shmem file to back the\nmapping. If __mmap_new_vma() subsequently fails, this replacement\nfile is never fput()'d - the original is released by\nksys_mmap_pgoff(), but nobody releases the new one.\n\nAdd fput() for the swapped file in the error path.\n\nReproducible with fault injection.\n\nFAULT_INJECTION: forcing a failure.\nname failslab, interval 1, probability 0, space 0, times 1\nCPU: 2 UID: 0 PID: 366 Comm: syz.7.14 Not tainted 7.0.0-rc6 #2 PREEMPT(full)\nHardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\nCall Trace:\n \u003cTASK\u003e\n dump_stack_lvl+0x164/0x1f0\n should_fail_ex+0x525/0x650\n should_failslab+0xdf/0x140\n kmem_cache_alloc_noprof+0x78/0x630\n vm_area_alloc+0x24/0x160\n __mmap_region+0xf6b/0x2660\n mmap_region+0x2eb/0x3a0\n do_mmap+0xc79/0x1240\n vm_mmap_pgoff+0x252/0x4c0\n ksys_mmap_pgoff+0xf8/0x120\n __x64_sys_mmap+0x12a/0x190\n do_syscall_64+0xa9/0x580\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n \u003c/TASK\u003e\n\nkmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak)\nBUG: memory leak\nunreferenced object 0xffff8881118aca80 (size 360):\n  comm \"syz.7.14\", pid 366, jiffies 4294913255\n  hex dump (first 32 bytes):\n    00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .....N..........\n    ff ff ff ff ff ff ff ff c0 28 4d ae ff ff ff ff  .........(M.....\n  backtrace (crc db0f53bc):\n    kmem_cache_alloc_noprof+0x3ab/0x630\n    alloc_empty_file+0x5a/0x1e0\n    alloc_file_pseudo+0x135/0x220\n    __shmem_file_setup+0x274/0x420\n    shmem_zero_setup_desc+0x9c/0x170\n    mmap_zero_prepare+0x123/0x140\n    __mmap_region+0xdda/0x2660\n    mmap_region+0x2eb/0x3a0\n    do_mmap+0xc79/0x1240\n    vm_mmap_pgoff+0x252/0x4c0\n    ksys_mmap_pgoff+0xf8/0x120\n    __x64_sys_mmap+0x12a/0x190\n    do_syscall_64+0xa9/0x580\n    entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\nFound by syzkaller.","modified":"2026-07-15T01:49:14.865488561Z","published":"2026-04-24T14:45:06.387Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31654.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/61fc8eaf2ab214b32c7bce52597c80cf0ca41ada"},{"type":"WEB","url":"https://git.kernel.org/stable/c/894f99eb535edc4514f756818f3c4f688ba53a59"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31654.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-31654"},{"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":"605f6586ecf78395f0185ab24c368fb46a06e434"},{"fixed":"61fc8eaf2ab214b32c7bce52597c80cf0ca41ada"},{"fixed":"894f99eb535edc4514f756818f3c4f688ba53a59"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31654.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.13"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31654.json"}}],"schema_version":"1.7.5"}