cbcvebase.
CVE-2025-21999
published 2025-04-03

CVE-2025-21999: In the Linux kernel, the following vulnerability has been resolved: proc: fix UAF in proc_get_inode() Fix race between rmmod and /proc/XXX's inode…

PriorityP337high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.20%
10.0th percentile
In the Linux kernel, the following vulnerability has been resolved: proc: fix UAF in proc_get_inode() Fix race between rmmod and /proc/XXX's inode instantiation. The bug is that pde->proc_ops don't belong to /proc, it belongs to a module, therefore dereferencing it after /proc entry has been registered is a bug unless use_pde/unuse_pde() pair has been used. use_pde/unuse_pde can be avoided (2 atomic ops!) because pde->proc_ops never changes so information necessary for inode instantiation can be saved _before_ proc_register() in PDE itself and used later, avoiding pde->proc_ops->... dereference. rmmod lookup sys_delete_module proc_lookup_de pde_get(de); proc_get_inode(dir->i_sb, de); mod->exit() proc_remove remove_proc_subtree proc_entry_rundown(de); free_module(mod); if (S_ISREG(inode->i_mode)) if (de->proc_ops->proc_read_iter) --> As module is already freed, will trigger UAF BUG: unable to handle page fault for address: fffffbfff80a702b PGD 817fc4067 P4D 817fc4067 PUD 817fc0067 PMD 102ef4067 PTE 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 26 UID: 0 PID: 2667 Comm: ls Tainted: G Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:proc_get_inode+0x302/0x6e0 RSP: 0018:ffff88811c837998 EFLAGS: 00010a06 RAX: dffffc0000000000 RBX: ffffffffc0538140 RCX: 0000000000000007 RDX: 1ffffffff80a702b RSI: 0000000000000001 RDI: ffffffffc0538158 RBP: ffff8881299a6000 R08: 0000000067bbe1e5 R09: 1ffff11023906f20 R10: ffffffffb560ca07 R11: ffffffffb2b43a58 R12: ffff888105bb78f0 R13: ffff888100518048 R14: ffff8881299a6004 R15: 0000000000000001 FS: 00007f95b9686840(0000) GS:ffff8883af100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: fffffbfff80a702b CR3: 0000000117dd2000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: proc_lookup_de+0x11f/0x2e0 __lookup_slow+0x188/0x350 walk_component+0x2ab/0x4f0 path_loo

Affected

28 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.133-1 (bookworm)linux 6.1.133-1 (bookworm)
debianlinux-6.1< linux 6.1.133-1 (bookworm)linux 6.1.133-1 (bookworm)
linuxlinux
linuxlinux>= 97a32539b9568bb653683349e5a76d02ff3c3e2c < eda279586e571b05dff44d48e05f8977ad05855deda279586e571b05dff44d48e05f8977ad05855d
linuxlinux>= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa
linuxlinux>= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 966f331403dc3ed04ff64eaf3930cf1267965e53966f331403dc3ed04ff64eaf3930cf1267965e53
linuxlinux>= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 63b53198aff2e4e6c5866a4ff73c7891f958ffa463b53198aff2e4e6c5866a4ff73c7891f958ffa4
linuxlinux>= 97a32539b9568bb653683349e5a76d02ff3c3e2c < ede3e8ac90ae106f0b29cd759aadebc1568f1308ede3e8ac90ae106f0b29cd759aadebc1568f1308
linuxlinux>= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 64dc7c68e040251d9ec6e989acb69f8f6ae4a10b64dc7c68e040251d9ec6e989acb69f8f6ae4a10b
linuxlinux>= 97a32539b9568bb653683349e5a76d02ff3c3e2c < 654b33ada4ab5e926cd9c570196fefa7bec7c1df654b33ada4ab5e926cd9c570196fefa7bec7c1df
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel
linuxlinux_kernel>= 0 < 5.10.237-15.10.237-1
linuxlinux_kernel>= 0 < 6.1.133-16.1.133-1
linuxlinux_kernel>= 0 < 6.12.21-16.12.21-1
linuxlinux_kernel>= 0 < 6.12.21-16.12.21-1
linuxlinux_kernel>= 0 < 5.15.0-142.1525.15.0-142.152
linuxlinux_kernel>= 0 < 6.8.0-84.846.8.0-84.84
linuxlinux_kernel>= 2.6.23 < 6.1.1326.1.132
linuxlinux_kernel>= 6.13 < 6.13.96.13.9
linuxlinux_kernel>= 6.2 < 6.6.856.6.85
linuxlinux_kernel>= 6.7 < 6.12.216.12.21
msrcazl3_kernel_6.6.82.1-1_on_azure_linux_3.0

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv8.8HIGH
vendor_ubuntu8.8HIGH
vendor_debian7.8HIGH
vendor_msrc7.8HIGH
vendor_redhat7.8HIGH
Stop checking back — get the weekly exploitation signal.

Every Monday: what got weaponized or added to CISA KEV in the last seven days — each CVE cross-linked to its PoC, Nuclei template, and detection rule. Free, one email a week, unsubscribe in one click.