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Fencer Vulns
high 7.8

CVE-2025-21999 json

proc: fix UAF in proc_get_inode()

published 2025-04-03 19 mo ago modified 2026-10-15 25 d ago also EUVD-2025-9588

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

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: <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

[adobriyan@gmail.com: don't do 2 atomic ops on the common path]

Patch / fix

  • Linux Linux 5.10.236, 5.15.180, 6.1.132, 6.6.85, 6.12.21, 6.13.9, 6.14
  • linux Debian 12 6.1.133-1
  • linux Debian 14, Debian 13 6.12.21-1

debian advisories DEBIAN-CVE-2025-21999

  • linux Ubuntu 22.04 LTS 5.15.0-142.152
  • linux Ubuntu 24.04 LTS 6.8.0-84.84
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1086.93
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1039.41
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1085.94
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1040.42
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1083.89
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1036.40

ubuntu advisories UBUNTU-CVE-2025-21999

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel RHEL 10.0 6.12.0-55.18.1.el10_0
  • rv RHEL 10.0 6.12.0-55.18.1.el10_0
  • perf RHEL 10.0 6.12.0-55.18.1.el10_0
  • rtla RHEL 10.0 6.12.0-55.18.1.el10_0
  • libperf RHEL 10.0 6.12.0-55.18.1.el10_0
  • kernel-rt RHEL 10.0 6.12.0-55.18.1.el10_0
  • kernel-64k RHEL 10.0 6.12.0-55.18.1.el10_0
  • kernel-core RHEL 10.0 6.12.0-55.18.1.el10_0

red hat advisories RHSA-2026:21209RHSA-2026:20593RHSA-2026:19875RHSA-2025:9348RHSA-2025:9080

  • kernel-livepatch-MICRO-6-0-RT_Update_2 Linux Micro 6.1, Linux Micro 6.0 11-1.1
  • kernel-livepatch-MICRO-6-0_Update_2 Linux Micro 6.1, Linux Micro 6.0 11-1.1
  • kernel-livepatch-MICRO-6-0_Update_5 Linux Micro 6.1, Linux Micro 6.0 7-1.2
  • kernel-livepatch-MICRO-6-0-RT_Update_3 Linux Micro 6.0 11-1.2
  • kernel-livepatch-MICRO-6-0-RT_Update_4 Linux Micro 6.1, Linux Micro 6.0 8-1.1
  • kernel-livepatch-MICRO-6-0-RT_Update_5 Linux Micro 6.1, Linux Micro 6.0 7-1.1
  • kernel-livepatch-MICRO-6-0-RT_Update_6 Linux Micro 6.1, Linux Micro 6.0 5-3.1
  • kernel-livepatch-MICRO-6-0-RT_Update_7 Linux Micro 6.1, Linux Micro 6.0 5-1.3

suse advisories SUSE-SU-2025:03235-1SUSE-SU-2025:03226-1SUSE-SU-2025:03223-1SUSE-SU-2025:03217-1SUSE-SU-2025:03215-1SUSE-SU-2025:03212-1

  • kernel AlmaLinux 9 5.14.0-570.22.1.el9_6
  • rv AlmaLinux 9 5.14.0-570.22.1.el9_6
  • perf AlmaLinux 9 5.14.0-570.22.1.el9_6
  • rtla AlmaLinux 9 5.14.0-570.22.1.el9_6
  • libperf AlmaLinux 9 5.14.0-570.22.1.el9_6
  • kernel-rt AlmaLinux 9 5.14.0-570.22.1.el9_6
  • kernel-64k AlmaLinux 9 5.14.0-570.22.1.el9_6
  • kernel-core AlmaLinux 9 5.14.0-570.22.1.el9_6

almalinux advisories ALSA-2025:9080

  • kernel Rocky Linux 10 6.12.0-55.18.1.el10_0

rocky linux advisories RLSA-2025:9348

  • kernel CBL-Mariner 2.0 5.15.180.1-1
  • kernel Azure Linux 3.0 6.6.85.1-2

azure linux advisories AZL-59604AZL-59651

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2025-21999 updated cvss 6.4

kernel: proc: fix UAF in proc_get_inode()

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.4) libperf 5.14.0-427.127.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.127.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.127.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.127.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.127.1.el9_4
    fixed: vendor fix RHSA-2026:21209
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-570.22.1.el9_6, perf 5.14.0-570.22.1.el9_6, rtla 5.14.0-570.22.1.el9_6, python3-perf 5.14.0-570.22.1.el9_6, kernel-devel-matched 5.14.0-570.22.1.el9_6, kernel-64k-devel-matched 5.14.0-570.22.1.el9_6, +7 more
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-55.18.1.el10_0, perf 6.12.0-55.18.1.el10_0, rtla 6.12.0-55.18.1.el10_0, python3-perf 6.12.0-55.18.1.el10_0, kernel-devel-matched 6.12.0-55.18.1.el10_0, kernel-64k-devel-matched 6.12.0-55.18.1.el10_0, +7 more
    fixed: vendor fix RHSA-2025:9348
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) perf 5.14.0-284.172.1.el9_2, rtla 5.14.0-284.172.1.el9_2, kernel-devel-matched 5.14.0-284.172.1.el9_2, kernel-64k-devel-matched 5.14.0-284.172.1.el9_2, kernel-debug-devel-matched 5.14.0-284.172.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.172.1.el9_2, +5 more
    fixed: vendor fix RHSA-2026:20593
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) rv 5.14.0-427.127.1.el9_4, perf 5.14.0-427.127.1.el9_4, rtla 5.14.0-427.127.1.el9_4, kernel-devel-matched 5.14.0-427.127.1.el9_4, kernel-64k-devel-matched 5.14.0-427.127.1.el9_4, kernel-debug-devel-matched 5.14.0-427.127.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:21209
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-570.22.1.el9_6, kernel-64k 5.14.0-570.22.1.el9_6, kernel-core 5.14.0-570.22.1.el9_6, kernel-tools 5.14.0-570.22.1.el9_6, kernel-modules 5.14.0-570.22.1.el9_6, kernel-64k-core 5.14.0-570.22.1.el9_6, +27 more
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-55.18.1.el10_0, kernel-64k 6.12.0-55.18.1.el10_0, kernel-core 6.12.0-55.18.1.el10_0, kernel-tools 6.12.0-55.18.1.el10_0, kernel-modules 6.12.0-55.18.1.el10_0, kernel-64k-core 6.12.0-55.18.1.el10_0, +27 more
    fixed: vendor fix RHSA-2025:9348
show 13 more
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool 7.0.0-284.172.1.el9_2, kernel 5.14.0-284.172.1.el9_2, kernel-64k 5.14.0-284.172.1.el9_2, kernel-core 5.14.0-284.172.1.el9_2, kernel-tools 5.14.0-284.172.1.el9_2, python3-perf 5.14.0-284.172.1.el9_2, +28 more
    fixed: vendor fix RHSA-2026:20593
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool 7.3.0-427.127.1.el9_4, kernel 5.14.0-427.127.1.el9_4, kernel-64k 5.14.0-427.127.1.el9_4, kernel-core 5.14.0-427.127.1.el9_4, kernel-tools 5.14.0-427.127.1.el9_4, python3-perf 5.14.0-427.127.1.el9_4, +28 more
    fixed: vendor fix RHSA-2026:21209
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-570.22.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.22.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.22.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.22.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.22.1.el9_6
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-55.18.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.18.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.18.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.18.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.18.1.el10_0
    fixed: vendor fix RHSA-2025:9348
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-570.22.1.el9_6, kernel-rt-64k 5.14.0-570.22.1.el9_6, kernel-rt-core 5.14.0-570.22.1.el9_6, kernel-rt-modules 5.14.0-570.22.1.el9_6, kernel-rt-64k-core 5.14.0-570.22.1.el9_6, kernel-rt-debug-core 5.14.0-570.22.1.el9_6, +14 more
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-55.18.1.el10_0, kernel-rt-64k 6.12.0-55.18.1.el10_0, kernel-rt-core 6.12.0-55.18.1.el10_0, kernel-rt-modules 6.12.0-55.18.1.el10_0, kernel-rt-64k-core 6.12.0-55.18.1.el10_0, kernel-rt-debug-core 6.12.0-55.18.1.el10_0, +14 more
    fixed: vendor fix RHSA-2025:9348
  • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-core 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-modules 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-debug-core 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-modules-core 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-debug-modules 5.14.0-284.172.1.rt14.457.el9_2, +4 more
    fixed: vendor fix RHSA-2026:19875
  • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt 5.14.0-427.127.1.el9_4, kernel-rt-core 5.14.0-427.127.1.el9_4, kernel-rt-modules 5.14.0-427.127.1.el9_4, kernel-rt-debug-core 5.14.0-427.127.1.el9_4, kernel-rt-modules-core 5.14.0-427.127.1.el9_4, kernel-rt-debug-modules 5.14.0-427.127.1.el9_4, +4 more
    fixed: vendor fix RHSA-2026:21209
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-570.22.1.el9_6, kernel-rt-kvm 5.14.0-570.22.1.el9_6, kernel-rt-core 5.14.0-570.22.1.el9_6, kernel-rt-modules 5.14.0-570.22.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.22.1.el9_6, kernel-rt-debug-core 5.14.0-570.22.1.el9_6, +6 more
    fixed: vendor fix RHSA-2025:9080
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-55.18.1.el10_0, kernel-rt-kvm 6.12.0-55.18.1.el10_0, kernel-rt-core 6.12.0-55.18.1.el10_0, kernel-rt-modules 6.12.0-55.18.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.18.1.el10_0, kernel-rt-debug-core 6.12.0-55.18.1.el10_0, +6 more
    fixed: vendor fix RHSA-2025:9348
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-kvm 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-core 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-modules 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-debug-kvm 5.14.0-284.172.1.rt14.457.el9_2, kernel-rt-debug-core 5.14.0-284.172.1.rt14.457.el9_2, +6 more
    fixed: vendor fix RHSA-2026:19875
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt 5.14.0-427.127.1.el9_4, kernel-rt-kvm 5.14.0-427.127.1.el9_4, kernel-rt-core 5.14.0-427.127.1.el9_4, kernel-rt-modules 5.14.0-427.127.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.127.1.el9_4, kernel-rt-debug-core 5.14.0-427.127.1.el9_4, +6 more
    fixed: vendor fix RHSA-2026:21209
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-26-295-11 updated cvss 7.8

Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.7 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.7 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.7
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

cisa ICSA-26-209-04 updated cvss 7.8

Siemens SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.6 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.6 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.6
    affected: mitigation, no fix available

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
19 mo ago

Exploit prediction

0.23% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CISA ADP 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux
  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP
  • Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP
  • Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

Classification

Weakness
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.