{"id":"CVE-2025-21999","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nproc: fix UAF in proc_get_inode()\n\nFix race between rmmod and /proc/XXX's inode instantiation.\n\nThe bug is that pde->proc_ops don't belong to /proc, it belongs to a\nmod…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nproc: fix UAF in proc_get_inode()\n\nFix race between rmmod and /proc/XXX's inode instantiation.\n\nThe bug is that pde->proc_ops don't belong to /proc, it belongs to a\nmod…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwe":["CWE-416"],"vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 2.6.23, < 6.1.132","linux_kernel >= 6.2, < 6.6.85","linux_kernel >= 6.7, < 6.12.21","linux_kernel >= 6.13, < 6.13.9","linux_kernel = 6.14"],"patched":["linux_kernel 6.13.9"],"published":"2025-04-03","updated":"2026-07-14","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2025-21999","references":[{"url":"https://git.kernel.org/stable/c/4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/63b53198aff2e4e6c5866a4ff73c7891f958ffa4","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/64dc7c68e040251d9ec6e989acb69f8f6ae4a10b","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/654b33ada4ab5e926cd9c570196fefa7bec7c1df","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/966f331403dc3ed04ff64eaf3930cf1267965e53","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/eda279586e571b05dff44d48e05f8977ad05855d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ede3e8ac90ae106f0b29cd759aadebc1568f1308","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-019113.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","cve.org"],"epss":0.00228,"epssPercentile":0.13831,"ingestedAt":"2026-07-14T13:36:56.146Z","ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2025-04-03T15:26:31.372538Z"},"slug":"CVE-2025-21999","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nproc: fix UAF in proc_get_inode()\n\nFix race between rmmod and /proc/XXX's inode instantiation.\n\nThe bug is that pde->proc_ops don't belong to /proc, it belongs to a\nmodule, therefore dereferencing it after /proc entry has been registered\nis a bug unless use_pde/unuse_pde() pair has been used.\n\nuse_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops\nnever changes so information necessary for inode instantiation can be\nsaved _before_ proc_register() in PDE itself and used later, avoiding\npde->proc_ops->...  dereference.\n\n      rmmod                         lookup\nsys_delete_module\n                         proc_lookup_de\n\t\t\t   pde_get(de);\n\t\t\t   proc_get_inode(dir->i_sb, de);\n  mod->exit()\n    proc_remove\n      remove_proc_subtree\n       proc_entry_rundown(de);\n  free_module(mod);\n\n                               if (S_ISREG(inode->i_mode))\n\t                         if (de->proc_ops->proc_read_iter)\n                           --> As module is already freed, will trigger UAF\n\nBUG: unable to handle page fault for address: fffffbfff80a702b\nPGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0\nOops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI\nCPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996)\nRIP: 0010:proc_get_inode+0x302/0x6e0\nRSP: 0018:ffff88811c837998 EFLAGS: 00010a06\nRAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007\nRDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158\nRBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20\nR10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78f0\nR13: ffff888100518048 R14: ffff8881299a6004 R15: 0000000000000001\nFS:  00007f95b9686840(0000) GS:ffff8883af100000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: fffffbfff80a702b CR3: 0000000117dd2000 CR4: 00000000000006f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nCall Trace:\n <TASK>\n proc_lookup_de+0x11f/0x2e0\n __lookup_slow+0x188/0x350\n walk_component+0x2ab/0x4f0\n path_lookupat+0x120/0x660\n filename_lookup+0x1ce/0x560\n vfs_statx+0xac/0x150\n __do_sys_newstat+0x96/0x110\n do_syscall_64+0x5f/0x170\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n\n[adobriyan@gmail.com: don't do 2 atomic ops on the common path]\n\n## Affected\n\n- `linux_kernel >= 2.6.23, < 6.1.132`\n- `linux_kernel >= 6.2, < 6.6.85`\n- `linux_kernel >= 6.7, < 6.12.21`\n- `linux_kernel >= 6.13, < 6.13.9`\n- `linux_kernel = 6.14`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 6.13.9`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}