{"id":"CVE-2026-31654","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-31654","generatedAt":"2026-10-28T05:59:53.882Z","title":"In the Linux kernel, the following vulnerability has been resolved: mm/vma: fix memory leak in __mmap_region() commit 605f6586ecf7 (\"mm/vma: do not leak memory when .mmap_prepare swaps the file\") handled the success path by skipping get_file() via…","description":"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 <TASK>\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 </TASK>\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.","published":"2026-04-24T15:16:45.000Z","lastModified":"2026-06-17T10:34:10.000Z","status":"Analyzed","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":{"version":"3.1","score":5.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-401"],"affected":["linux/linux kernel"],"epss":{"score":0.00113,"percentile":0.01411,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.11%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/61fc8eaf2ab214b32c7bce52597c80cf0ca41ada","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/894f99eb535edc4514f756818f3c4f688ba53a59","tags":["Patch"],"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-31654","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}