proc: fix UAF in proc_get_inode()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2025-21999
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2025-04-03 08:15:15 UTC
Updated2026-07-14 13:17:28 UTC
DescriptionIn 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: <TASK> proc_lookup_de+0x11f/0x2e0 __lookup_slow+0x188/0x350 walk_component+0x2ab/0x4f0 path_lookupat+0x120/0x660 filename_lookup+0x1ce/0x560 vfs_statx+0xac/0x150 __do_sys_newstat+0x96/0x110 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e [[email protected]: don't do 2 atomic ops on the common path]

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from ADP

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Problem Types: CWE-416 | CWE-416 CWE-416 Use After Free

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 97a32539b9568bb653683349e5a76d02ff3c3e2c eda279586e571b05dff44d48e05f8977ad05855d git Not specified
CNA Linux Linux affected 97a32539b9568bb653683349e5a76d02ff3c3e2c 4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa git Not specified
CNA Linux Linux affected 97a32539b9568bb653683349e5a76d02ff3c3e2c 966f331403dc3ed04ff64eaf3930cf1267965e53 git Not specified
CNA Linux Linux affected 97a32539b9568bb653683349e5a76d02ff3c3e2c 63b53198aff2e4e6c5866a4ff73c7891f958ffa4 git Not specified
CNA Linux Linux affected 97a32539b9568bb653683349e5a76d02ff3c3e2c ede3e8ac90ae106f0b29cd759aadebc1568f1308 git Not specified
CNA Linux Linux affected 97a32539b9568bb653683349e5a76d02ff3c3e2c 64dc7c68e040251d9ec6e989acb69f8f6ae4a10b git Not specified
CNA Linux Linux affected 97a32539b9568bb653683349e5a76d02ff3c3e2c 654b33ada4ab5e926cd9c570196fefa7bec7c1df git Not specified
CNA Linux Linux affected 5.6 Not specified
CNA Linux Linux unaffected 5.6 semver Not specified
CNA Linux Linux unaffected 5.10.236 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.180 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.132 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.85 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.21 6.12.* semver Not specified
CNA Linux Linux unaffected 6.13.9 6.13.* semver Not specified
CNA Linux Linux unaffected 6.14 * original_commit_for_fix Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP affected V3.1.6 * custom Not specified
ADP Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP affected V3.1.6 * custom Not specified

References

ReferenceSourceLinkTags
lists.debian.org/debian-lts-announce/2025/05/msg00030.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org
git.kernel.org/stable/c/654b33ada4ab5e926cd9c570196fefa7bec7c1df 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/63b53198aff2e4e6c5866a4ff73c7891f958ffa4 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/ede3e8ac90ae106f0b29cd759aadebc1568f1308 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/eda279586e571b05dff44d48e05f8977ad05855d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/64dc7c68e040251d9ec6e989acb69f8f6ae4a10b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
cert-portal.siemens.com/productcert/html/ssa-019113.html 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e cert-portal.siemens.com
git.kernel.org/stable/c/966f331403dc3ed04ff64eaf3930cf1267965e53 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/4b0b8445b6fd41e6f62ac90547a0ea9d348de3fa 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
lists.debian.org/debian-lts-announce/2025/05/msg00045.html af854a3a-2127-422b-91ae-364da2661108 lists.debian.org
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