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Fencer Vulns
medium 5.5

CVE-2024-40995 json

net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc()

published 2024-07-12 2 y ago modified 2026-10-15 25 d ago also EUVD-2024-38790

cvss
5.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

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

net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc()

syzbot found hanging tasks waiting on rtnl_lock [1]

A reproducer is available in the syzbot bug.

When a request to add multiple actions with the same index is sent, the second request will block forever on the first request. This holds rtnl_lock, and causes tasks to hang.

Return -EAGAIN to prevent infinite looping, while keeping documented behavior.

[1]

INFO: task kworker/1:0:5088 blocked for more than 143 seconds. Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:0 state:D stack:23744 pid:5088 tgid:5088 ppid:2 flags:0x00004000 Workqueue: events_power_efficient reg_check_chans_work Call Trace: <TASK> context_switch kernel/sched/core.c:5409 [inline] __schedule+0xf15/0x5d00 kernel/sched/core.c:6746 __schedule_loop kernel/sched/core.c:6823 [inline] schedule+0xe7/0x350 kernel/sched/core.c:6838 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6895 __mutex_lock_common kernel/locking/mutex.c:684 [inline] __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752 wiphy_lock include/net/cfg80211.h:5953 [inline] reg_leave_invalid_chans net/wireless/reg.c:2466 [inline] reg_check_chans_work+0x10a/0x10e0 net/wireless/reg.c:2481

Patch / fix

  • Linux Linux 5.4.279, 5.10.221, 5.15.162, 6.1.96, 6.6.36, 6.9.7, 6.10
  • Siemens RUGGEDCOM RST2428P V3.1
  • Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family V3.1
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem V1.1.1
  • linux Debian 12 6.1.99-1
  • linux Debian 14, Debian 13 6.9.7-1

debian advisories DEBIAN-CVE-2024-40995

  • linux Ubuntu 20.04 LTS 5.4.0-195.215
  • linux Ubuntu 22.04 LTS 5.15.0-121.131
  • linux Ubuntu 24.04 LTS 6.8.0-44.44
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1132.142
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1069.75
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1015.16
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1136.145
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1068.76

ubuntu advisories UBUNTU-CVE-2024-40995

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 9 5.14.0-427.42.1.el9_4
  • rv RHEL 9 5.14.0-427.42.1.el9_4
  • perf RHEL 9 5.14.0-427.42.1.el9_4
  • rtla RHEL 9 5.14.0-427.42.1.el9_4
  • bpftool RHEL 9 7.3.0-427.42.1.el9_4
  • libperf RHEL 9 5.14.0-427.42.1.el9_4
  • kernel-rt RHEL 9 5.14.0-427.42.1.el9_4
  • kernel-64k RHEL 9 5.14.0-427.42.1.el9_4

red hat advisories RHSA-2024:8617RHSA-2024:6993RHSA-2024:7000RHSA-2024:7001RHSA-2024:6160RHSA-2024:6156

  • kernel-rt Linux Micro 6.0 6.4.0-10.1
  • kernel-source-rt Linux Micro 6.0 6.4.0-10.1
  • kernel-livepatch-MICRO-6-0-RT_Update_2 Linux Micro 6.0 1-1.1
  • kernel-source Linux Micro 6.0 6.4.0-19.1
  • kernel-default Linux Micro 6.0 6.4.0-19.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-19.1
  • kernel-default-base Linux Micro 6.0 6.4.0-17.1.1.51
  • kernel-livepatch-MICRO-6-0_Update_2 Linux Micro 6.0 1-1.1

suse advisories SUSE-SU-2025:20047-1SUSE-SU-2025:20044-1SUSE-SU-2024:3483-1SUSE-SU-2024:3383-1SUSE-SU-2024:3209-1SUSE-SU-2024:3195-1

  • kernel AlmaLinux 9 5.14.0-427.42.1.el9_4
  • rv AlmaLinux 9 5.14.0-427.42.1.el9_4
  • perf AlmaLinux 9 5.14.0-427.42.1.el9_4
  • rtla AlmaLinux 9 5.14.0-427.42.1.el9_4
  • bpftool AlmaLinux 9 7.3.0-427.42.1.el9_4
  • libperf AlmaLinux 9 5.14.0-427.42.1.el9_4
  • kernel-rt AlmaLinux 9 5.14.0-427.42.1.el9_4
  • kernel-64k AlmaLinux 9 5.14.0-427.42.1.el9_4

almalinux advisories ALSA-2024:8617ALSA-2024:7000ALSA-2024:7001

  • kernel Rocky Linux 8 4.18.0-553.22.1.el8_10
  • kernel Rocky Linux 9 5.14.0-427.42.1.el9_4
  • kernel-rt Rocky Linux 8 4.18.0-553.22.1.rt7.363.el8_10

rocky linux advisories RLSA-2024:7000RLSA-2024:8617RLSA-2024:7001

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-2024-40995 updated cvss 5.5

kernel: net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc()

  • 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
    affected: workaround, no fix planned “Out of support scope”
  • 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.8.8) kernel-debuginfo-common-x86_64 4.18.0-477.74.1.el8_8, kernel-debuginfo-common-aarch64 4.18.0-477.74.1.el8_8, kernel-debuginfo-common-ppc64le 4.18.0-477.74.1.el8_8
    fixed: vendor fix RHSA-2024:6993
  • Red Hat CodeReady Linux Builder EUS (v.9.2) kernel-debuginfo-common-s390x 5.14.0-284.80.1.el9_2, kernel-debuginfo-common-x86_64 5.14.0-284.80.1.el9_2, kernel-debuginfo-common-aarch64 5.14.0-284.80.1.el9_2, kernel-debuginfo-common-ppc64le 5.14.0-284.80.1.el9_2
    fixed: vendor fix RHSA-2024:5672
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-427.42.1.el9_4, perf 5.14.0-427.42.1.el9_4, rtla 5.14.0-427.42.1.el9_4, kernel-devel-matched 5.14.0-427.42.1.el9_4, kernel-64k-devel-matched 5.14.0-427.42.1.el9_4, kernel-debug-devel-matched 5.14.0-427.42.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:8617
  • Red Hat Enterprise Linux AppStream E4S (v.9.0) perf 5.14.0-70.117.1.el9_0, kernel-devel-matched 5.14.0-70.117.1.el9_0, kernel-debug-devel-matched 5.14.0-70.117.1.el9_0, kernel-debuginfo-common-s390x 5.14.0-70.117.1.el9_0, kernel-zfcpdump-devel-matched 5.14.0-70.117.1.el9_0, kernel-debuginfo-common-x86_64 5.14.0-70.117.1.el9_0, +2 more
    fixed: vendor fix RHSA-2024:6991
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) perf 5.14.0-284.80.1.el9_2, rtla 5.14.0-284.80.1.el9_2, kernel-devel-matched 5.14.0-284.80.1.el9_2, kernel-64k-devel-matched 5.14.0-284.80.1.el9_2, kernel-debug-devel-matched 5.14.0-284.80.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.80.1.el9_2, +5 more
    fixed: vendor fix RHSA-2024:5672
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.22.1.el8_10, kernel 4.18.0-553.22.1.el8_10, bpftool 4.18.0-553.22.1.el8_10, kernel-core 4.18.0-553.22.1.el8_10, kernel-tools 4.18.0-553.22.1.el8_10, python3-perf 4.18.0-553.22.1.el8_10, +15 more
    fixed: vendor fix RHSA-2024:7000
show 19 more
  • Red Hat Enterprise Linux BaseOS (v. 9) bpftool 7.3.0-427.42.1.el9_4, kernel 5.14.0-427.42.1.el9_4, kernel-64k 5.14.0-427.42.1.el9_4, kernel-core 5.14.0-427.42.1.el9_4, kernel-tools 5.14.0-427.42.1.el9_4, python3-perf 5.14.0-427.42.1.el9_4, +28 more
    fixed: vendor fix RHSA-2024:8617
  • Red Hat Enterprise Linux BaseOS AUS (v.8.4) perf 4.18.0-305.139.1.el8_4, kernel 4.18.0-305.139.1.el8_4, bpftool 4.18.0-305.139.1.el8_4, kernel-core 4.18.0-305.139.1.el8_4, kernel-tools 4.18.0-305.139.1.el8_4, python3-perf 4.18.0-305.139.1.el8_4, +8 more Red Hat Enterprise Linux BaseOS E4S (v.8.4) perf 4.18.0-305.139.1.el8_4, kernel 4.18.0-305.139.1.el8_4, bpftool 4.18.0-305.139.1.el8_4, kernel-core 4.18.0-305.139.1.el8_4, kernel-tools 4.18.0-305.139.1.el8_4, python3-perf 4.18.0-305.139.1.el8_4, +9 more
    fixed: vendor fix RHSA-2024:6156
  • Red Hat Enterprise Linux BaseOS E4S (v.9.0) kernel 5.14.0-70.117.1.el9_0, bpftool 5.14.0-70.117.1.el9_0, kernel-core 5.14.0-70.117.1.el9_0, kernel-tools 5.14.0-70.117.1.el9_0, python3-perf 5.14.0-70.117.1.el9_0, kernel-modules 5.14.0-70.117.1.el9_0, +14 more
    fixed: vendor fix RHSA-2024:6991
  • Red Hat Enterprise Linux BaseOS EUS (v.8.8) perf 4.18.0-477.74.1.el8_8, kernel 4.18.0-477.74.1.el8_8, bpftool 4.18.0-477.74.1.el8_8, kernel-core 4.18.0-477.74.1.el8_8, kernel-tools 4.18.0-477.74.1.el8_8, python3-perf 4.18.0-477.74.1.el8_8, +15 more
    fixed: vendor fix RHSA-2024:6993
  • Red Hat Enterprise Linux BaseOS EUS (v.9.2) bpftool 7.0.0-284.80.1.el9_2, kernel 5.14.0-284.80.1.el9_2, kernel-64k 5.14.0-284.80.1.el9_2, kernel-core 5.14.0-284.80.1.el9_2, kernel-tools 5.14.0-284.80.1.el9_2, python3-perf 5.14.0-284.80.1.el9_2, +28 more
    fixed: vendor fix RHSA-2024:5672
  • Red Hat Enterprise Linux BaseOS TUS (v.8.4) perf 4.18.0-305.139.1.el8_4, kernel 4.18.0-305.139.1.el8_4, bpftool 4.18.0-305.139.1.el8_4, kernel-core 4.18.0-305.139.1.el8_4, kernel-tools 4.18.0-305.139.1.el8_4, python3-perf 4.18.0-305.139.1.el8_4, +8 more
    fixed: vendor fix RHSA-2024:6156
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.22.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.22.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.22.1.el8_10
    fixed: vendor fix RHSA-2024:7000
  • Red Hat Enterprise Linux CRB (v. 9) libperf 5.14.0-427.42.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.42.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.42.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.42.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.42.1.el9_4
    fixed: vendor fix RHSA-2024:8617
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-kvm 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-kvm 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-core 4.18.0-553.22.1.rt7.363.el8_10, +4 more
    fixed: vendor fix RHSA-2024:7001
  • Red Hat Enterprise Linux NFV (v. 9) kernel-rt 5.14.0-427.42.1.el9_4, kernel-rt-kvm 5.14.0-427.42.1.el9_4, kernel-rt-core 5.14.0-427.42.1.el9_4, kernel-rt-modules 5.14.0-427.42.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.42.1.el9_4, kernel-rt-debug-core 5.14.0-427.42.1.el9_4, +6 more
    fixed: vendor fix RHSA-2024:8617
  • Red Hat Enterprise Linux NFV E4S (v.9.0) kernel-rt 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-kvm 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-core 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-modules 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-debug-kvm 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-debug-core 5.14.0-70.117.1.rt21.189.el9_0, +4 more
    fixed: vendor fix RHSA-2024:6990
  • Red Hat Enterprise Linux NFV TUS (v.8.4) kernel-rt 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-kvm 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-core 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-modules 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-debug-kvm 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-debug-core 4.18.0-305.139.1.rt7.215.el8_4, +4 more
    fixed: vendor fix RHSA-2024:6160
  • Red Hat Enterprise Linux Real Time E4S (v.9.0) kernel-rt 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-core 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-modules 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-debug-core 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-debug-modules 5.14.0-70.117.1.rt21.189.el9_0, kernel-rt-modules-extra 5.14.0-70.117.1.rt21.189.el9_0, +2 more
    fixed: vendor fix RHSA-2024:6990
  • Red Hat Enterprise Linux Real Time EUS (v.9.2) kernel-rt 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-core 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-modules 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-debug-core 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-modules-core 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-debug-modules 5.14.0-284.80.1.rt14.365.el9_2, +4 more Red Hat Enterprise Linux Real Time for NFV EUS (v.9.2) kernel-rt 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-kvm 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-core 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-modules 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-debug-kvm 5.14.0-284.80.1.rt14.365.el9_2, kernel-rt-debug-core 5.14.0-284.80.1.rt14.365.el9_2, +6 more
    fixed: vendor fix RHSA-2024:5673
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules-extra 4.18.0-553.22.1.rt7.363.el8_10, +2 more
    fixed: vendor fix RHSA-2024:7001
  • Red Hat Enterprise Linux RT (v. 9) kernel-rt 5.14.0-427.42.1.el9_4, kernel-rt-core 5.14.0-427.42.1.el9_4, kernel-rt-modules 5.14.0-427.42.1.el9_4, kernel-rt-debug-core 5.14.0-427.42.1.el9_4, kernel-rt-modules-core 5.14.0-427.42.1.el9_4, kernel-rt-debug-modules 5.14.0-427.42.1.el9_4, +4 more
    fixed: vendor fix RHSA-2024:8617
  • Red Hat Enterprise Linux RT TUS (v.8.4) kernel-rt 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-core 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-modules 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-debug-core 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-debug-modules 4.18.0-305.139.1.rt7.215.el8_4, kernel-rt-modules-extra 4.18.0-305.139.1.rt7.215.el8_4, +2 more
    fixed: vendor fix RHSA-2024:6160
  • Red Hat OpenShift AI 8 rhoai/odh-rhel8-operator v2.13.1-2, rhoai/odh-dashboard-rhel8 v2.13.1-1, rhoai/odh-modelmesh-rhel8 v2.13.1-1, rhoai/odh-operator-bundle v2.13.1-2, rhoai/odh-rhel8-operator v2.14.0-24, rhoai/odh-dashboard-rhel8 v2.14.0-11, +56 more
    fixed: vendor fix RHBA-2024:8413
  • Red Hat Enterprise Linux AppStream EUS (v.9.2) kernel-doc 5.14.0-284.80.1.el9_2
    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-24-102-01 updated cvss 5.5

Siemens SIMATIC S7-1500 TM MFP

  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
    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-25-226-07 updated

Siemens Third-Party Components in SINEC OS

  • Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family
    not affected

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

cisa ICSA-25-226-15 updated cvss 5.5

Siemens SINEC OS

  • Siemens RUGGEDCOM RST2428P (6GK6242-6PA00) < 3.1 Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family < 3.1
    affected: fixed in V3.1 support.industry.siemens.com
  • Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family
    not affected

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
partial
Assessed
2 y ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
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 RUGGEDCOM RST2428P
  • Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family
  • Siemens SCALANCE XCM-/XRM-/XCH-/XRH-300 family
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition
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.