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Fencer Vulns
high 7.8

CVE-2025-38614 json

eventpoll: Fix semi-unbounded recursion

published 2025-08-19 14 mo ago modified 2026-10-15 24 d ago also EUVD-2025-25367

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 7%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

eventpoll: Fix semi-unbounded recursion

Ensure that epoll instances can never form a graph deeper than EP_MAX_NESTS+1 links.

Currently, ep_loop_check_proc() ensures that the graph is loop-free and does some recursion depth checks, but those recursion depth checks don't limit the depth of the resulting tree for two reasons:

- They don't look upwards in the tree. - If there are multiple downwards paths of different lengths, only one of the paths is actually considered for the depth check since commit 28d82dc1c4ed ("epoll: limit paths").

Essentially, the current recursion depth check in ep_loop_check_proc() just serves to prevent it from recursing too deeply while checking for loops.

A more thorough check is done in reverse_path_check() after the new graph edge has already been created; this checks, among other things, that no paths going upwards from any non-epoll file with a length of more than 5 edges exist. However, this check does not apply to non-epoll files.

As a result, it is possible to recurse to a depth of at least roughly 500, tested on v6.15. (I am unsure if deeper recursion is possible; and this may have changed with commit 8c44dac8add7 ("eventpoll: Fix priority inversion problem").)

To fix it:

1. In ep_loop_check_proc(), note the subtree depth of each visited node, and use subtree depths for the total depth calculation even when a subtree has already been visited. 2. Add ep_get_upwards_depth_proc() for similarly determining the maximum depth of an upwards walk. 3. In ep_loop_check(), use these values to limit the total path length between epoll nodes to EP_MAX_NESTS edges.

Patch / fix

  • Linux Linux 2.6.33, 2.6.34, 2.6.35, 2.6.36, 2.6.38, 5.15.190, 6.1.149, 6.6.103, 6.12.43, 6.15.11, 6.16.1, 6.17
  • Siemens SIMATIC CN 4100 V5.0
  • linux Debian 12 6.1.153-1
  • linux Debian 13 6.12.43-1
  • linux Debian 14 6.16.3-1

debian advisories DEBIAN-CVE-2025-38614

  • linux Ubuntu 22.04 LTS 5.15.0-163.173
  • linux Ubuntu 24.04 LTS 6.8.0-100.100
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1097.104
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1046.49
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1097.106
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1047.50
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1093.99
  • linux-gke Ubuntu 24.04 LTS 6.8.0-1043.48

ubuntu advisories UBUNTU-CVE-2025-38614

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 10.1 6.12.0-124.11.1.el10_1
  • rv RHEL 10.1 6.12.0-124.11.1.el10_1
  • perf RHEL 10.1 6.12.0-124.11.1.el10_1
  • rtla RHEL 10.1 6.12.0-124.11.1.el10_1
  • libperf RHEL 10.1 6.12.0-124.11.1.el10_1
  • kernel-rt RHEL 10.1 6.12.0-124.11.1.el10_1
  • kernel-64k RHEL 10.1 6.12.0-124.11.1.el10_1
  • kernel-core RHEL 10.1 6.12.0-124.11.1.el10_1

red hat advisories RHSA-2025:21463RHSA-2025:21128RHSA-2025:21051RHSA-2025:19492RHSA-2025:19268RHSA-2025:19104

  • kernel-rt Linux Micro 6.2 6.12.0-160000.6.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.6.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1.160000.2.4
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.6.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.6.1

suse advisories SUSE-SU-2025:21074-1SUSE-SU-2025:21139-1SUSE-SU-2026:20560-1SUSE-SU-2025:21179-1SUSE-SU-2025:20870-1SUSE-SU-2025:20898-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.6.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.6.1
  • kernel-kvmsmall openSUSE Leap 16.0 6.12.0-160000.6.1

opensuse advisories openSUSE-SU-2025:20081-1

  • kernel-abi-stablelists AlmaLinux 10 6.12.0-55.40.1.el10_0
  • kernel AlmaLinux 9 5.14.0-570.52.1.el9_6
  • rv AlmaLinux 9 5.14.0-570.52.1.el9_6
  • perf AlmaLinux 9 5.14.0-570.52.1.el9_6
  • rtla AlmaLinux 9 5.14.0-570.52.1.el9_6
  • libperf AlmaLinux 9 5.14.0-570.52.1.el9_6
  • kernel-rt AlmaLinux 9 5.14.0-570.52.1.el9_6
  • kernel-64k AlmaLinux 9 5.14.0-570.52.1.el9_6

almalinux advisories ALSA-2025:18318ALSA-2025:17760

  • kernel Rocky Linux 10 6.12.0-55.40.1.el10_0
  • kernel Rocky Linux 9 5.14.0-570.52.1.el9_6

rocky linux advisories RLSA-2025:18318RLSA-2025:17760

  • kernel Azure Linux 3.0 6.6.104.2-1
  • kernel CBL-Mariner 2.0 5.15.200.1-1

azure linux advisories AZL-66533AZL-73878

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-2025-38614 updated cvss 6.2

kernel: eventpoll: Fix semi-unbounded recursion

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: workaround, no fix planned “Out of support scope”
  • 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
    affected: workaround, no fix available, no fix planned “Will not fix”
  • 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: workaround, no fix available
  • Red Hat CodeReady Linux Builder EUS (v.9.4) libperf 5.14.0-427.96.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.96.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.96.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.96.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.96.1.el9_4
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-570.52.1.el9_6, perf 5.14.0-570.52.1.el9_6, rtla 5.14.0-570.52.1.el9_6, python3-perf 5.14.0-570.52.1.el9_6, kernel-devel-matched 5.14.0-570.52.1.el9_6, kernel-64k-devel-matched 5.14.0-570.52.1.el9_6, +7 more
    fixed: vendor fix RHSA-2025:17760
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-55.40.1.el10_0, rv 6.12.0-124.11.1.el10_1, perf 6.12.0-55.40.1.el10_0, rtla 6.12.0-55.40.1.el10_0, perf 6.12.0-124.11.1.el10_1, rtla 6.12.0-124.11.1.el10_1, +20 more
    fixed: vendor fix RHSA-2025:18318
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) perf 5.14.0-70.151.1.el9_0, kernel-devel-matched 5.14.0-70.151.1.el9_0, kernel-debug-devel-matched 5.14.0-70.151.1.el9_0, kernel-debuginfo-common-s390x 5.14.0-70.151.1.el9_0, kernel-zfcpdump-devel-matched 5.14.0-70.151.1.el9_0, kernel-debuginfo-common-x86_64 5.14.0-70.151.1.el9_0, +2 more
    fixed: vendor fix RHSA-2025:19492
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) perf 5.14.0-284.146.1.el9_2, rtla 5.14.0-284.146.1.el9_2, kernel-devel-matched 5.14.0-284.146.1.el9_2, kernel-64k-devel-matched 5.14.0-284.146.1.el9_2, kernel-debug-devel-matched 5.14.0-284.146.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.146.1.el9_2, +5 more
    fixed: vendor fix RHSA-2025:21051
show 18 more
  • Red Hat Enterprise Linux AppStream EUS (v.9.4) rv 5.14.0-427.96.1.el9_4, perf 5.14.0-427.96.1.el9_4, rtla 5.14.0-427.96.1.el9_4, kernel-devel-matched 5.14.0-427.96.1.el9_4, kernel-64k-devel-matched 5.14.0-427.96.1.el9_4, kernel-debug-devel-matched 5.14.0-427.96.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-570.52.1.el9_6, kernel-64k 5.14.0-570.52.1.el9_6, kernel-core 5.14.0-570.52.1.el9_6, kernel-tools 5.14.0-570.52.1.el9_6, kernel-modules 5.14.0-570.52.1.el9_6, kernel-64k-core 5.14.0-570.52.1.el9_6, +27 more
    fixed: vendor fix RHSA-2025:17760
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-55.40.1.el10_0, kernel 6.12.0-124.11.1.el10_1, kernel-64k 6.12.0-55.40.1.el10_0, kernel-64k 6.12.0-124.11.1.el10_1, kernel-core 6.12.0-55.40.1.el10_0, kernel-core 6.12.0-124.11.1.el10_1, +61 more
    fixed: vendor fix RHSA-2025:18318
  • Red Hat Enterprise Linux BaseOS E4S (v.9.0) kernel 5.14.0-70.151.1.el9_0, bpftool 5.14.0-70.151.1.el9_0, kernel-core 5.14.0-70.151.1.el9_0, kernel-tools 5.14.0-70.151.1.el9_0, python3-perf 5.14.0-70.151.1.el9_0, kernel-modules 5.14.0-70.151.1.el9_0, +14 more
    fixed: vendor fix RHSA-2025:19492
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool 7.0.0-284.146.1.el9_2, kernel 5.14.0-284.146.1.el9_2, kernel-64k 5.14.0-284.146.1.el9_2, kernel-core 5.14.0-284.146.1.el9_2, kernel-tools 5.14.0-284.146.1.el9_2, python3-perf 5.14.0-284.146.1.el9_2, +28 more
    fixed: vendor fix RHSA-2025:21051
  • Red Hat Enterprise Linux BaseOS EUS (v.9.4) bpftool 7.3.0-427.96.1.el9_4, kernel 5.14.0-427.96.1.el9_4, kernel-64k 5.14.0-427.96.1.el9_4, kernel-core 5.14.0-427.96.1.el9_4, kernel-tools 5.14.0-427.96.1.el9_4, python3-perf 5.14.0-427.96.1.el9_4, +28 more
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-570.52.1.el9_6, kernel-debuginfo-common-s390x 5.14.0-570.52.1.el9_6, kernel-debuginfo-common-x86_64 5.14.0-570.52.1.el9_6, kernel-debuginfo-common-aarch64 5.14.0-570.52.1.el9_6, kernel-debuginfo-common-ppc64le 5.14.0-570.52.1.el9_6
    fixed: vendor fix RHSA-2025:17760
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-55.40.1.el10_0, libperf 6.12.0-124.11.1.el10_1, kernel-debuginfo-common-s390x 6.12.0-55.40.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-124.11.1.el10_1, kernel-debuginfo-common-x86_64 6.12.0-55.40.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.40.1.el10_0, +4 more
    fixed: vendor fix RHSA-2025:18318
  • Red Hat Enterprise Linux NFV E4S (v.9.0) kernel-rt 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-kvm 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-core 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-modules 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-debug-kvm 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-debug-core 5.14.0-70.151.1.rt21.223.el9_0, +4 more
    fixed: vendor fix RHSA-2025:19268
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-570.52.1.el9_6, kernel-rt-64k 5.14.0-570.52.1.el9_6, kernel-rt-core 5.14.0-570.52.1.el9_6, kernel-rt-modules 5.14.0-570.52.1.el9_6, kernel-rt-64k-core 5.14.0-570.52.1.el9_6, kernel-rt-debug-core 5.14.0-570.52.1.el9_6, +14 more
    fixed: vendor fix RHSA-2025:17760
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-55.40.1.el10_0, kernel-rt 6.12.0-124.11.1.el10_1, kernel-rt-64k 6.12.0-55.40.1.el10_0, kernel-rt-64k 6.12.0-124.11.1.el10_1, kernel-rt-core 6.12.0-55.40.1.el10_0, kernel-rt-core 6.12.0-124.11.1.el10_1, +34 more
    fixed: vendor fix RHSA-2025:18318
  • Red Hat Enterprise Linux Real Time E4S (v.9.0) kernel-rt 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-core 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-modules 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-debug-core 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-debug-modules 5.14.0-70.151.1.rt21.223.el9_0, kernel-rt-modules-extra 5.14.0-70.151.1.rt21.223.el9_0, +2 more
    fixed: vendor fix RHSA-2025:19268
  • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-core 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-modules 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-debug-core 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-modules-core 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-debug-modules 5.14.0-284.146.1.rt14.431.el9_2, +4 more
    fixed: vendor fix RHSA-2025:21128
  • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt 5.14.0-427.96.1.el9_4, kernel-rt-core 5.14.0-427.96.1.el9_4, kernel-rt-modules 5.14.0-427.96.1.el9_4, kernel-rt-debug-core 5.14.0-427.96.1.el9_4, kernel-rt-modules-core 5.14.0-427.96.1.el9_4, kernel-rt-debug-modules 5.14.0-427.96.1.el9_4, +4 more
    fixed: vendor fix RHSA-2025:19104
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-570.52.1.el9_6, kernel-rt-kvm 5.14.0-570.52.1.el9_6, kernel-rt-core 5.14.0-570.52.1.el9_6, kernel-rt-modules 5.14.0-570.52.1.el9_6, kernel-rt-debug-kvm 5.14.0-570.52.1.el9_6, kernel-rt-debug-core 5.14.0-570.52.1.el9_6, +6 more
    fixed: vendor fix RHSA-2025:17760
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-55.40.1.el10_0, kernel-rt 6.12.0-124.11.1.el10_1, kernel-rt-kvm 6.12.0-55.40.1.el10_0, kernel-rt-core 6.12.0-55.40.1.el10_0, kernel-rt-core 6.12.0-124.11.1.el10_1, kernel-rt-modules 6.12.0-55.40.1.el10_0, +16 more
    fixed: vendor fix RHSA-2025:18318
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-kvm 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-core 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-modules 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-debug-kvm 5.14.0-284.146.1.rt14.431.el9_2, kernel-rt-debug-core 5.14.0-284.146.1.rt14.431.el9_2, +6 more
    fixed: vendor fix RHSA-2025:21128
  • Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt 5.14.0-427.96.1.el9_4, kernel-rt-kvm 5.14.0-427.96.1.el9_4, kernel-rt-core 5.14.0-427.96.1.el9_4, kernel-rt-modules 5.14.0-427.96.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.96.1.el9_4, kernel-rt-debug-core 5.14.0-427.96.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:19104

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 5.5

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 ICSA-25-162-05 updated cvss 5.5

Siemens SIMATIC S7-1500 CPU family

  • Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= 3.1.5 Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) >= 3.1.5 Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) >= 3.1.5
    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
24 d ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% 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
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux
  • Siemens SIMATIC CN 4100
  • 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.