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Fencer Intel
high 7.5

CVE-2024-26851 json

netfilter: nf_conntrack_h323: Add protection for bmp length out of range

published 2y ago modified 28d ago also EUVD-2024-24113

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 55%
public exploits
0
none known

Summary

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

netfilter: nf_conntrack_h323: Add protection for bmp length out of range

UBSAN load reports an exception of BRK#5515 SHIFT_ISSUE:Bitwise shifts that are out of bounds for their data type.

vmlinux get_bitmap(b=75) + 712 <net/netfilter/nf_conntrack_h323_asn1.c:0> vmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, level=134443100) + 1956 <net/netfilter/nf_conntrack_h323_asn1.c:592> vmlinux decode_choice(base=0xFFFFFFD0080370F0, level=23843636) + 1216 <net/netfilter/nf_conntrack_h323_asn1.c:814> vmlinux decode_seq(f=0xFFFFFFD0080371A8, level=134443500) + 812 <net/netfilter/nf_conntrack_h323_asn1.c:576> vmlinux decode_choice(base=0xFFFFFFD008037280, level=0) + 1216 <net/netfilter/nf_conntrack_h323_asn1.c:814> vmlinux DecodeRasMessage() + 304 <net/netfilter/nf_conntrack_h323_asn1.c:833> vmlinux ras_help() + 684 <net/netfilter/nf_conntrack_h323_main.c:1728> vmlinux nf_confirm() + 188 <net/netfilter/nf_conntrack_proto.c:137>

Due to abnormal data in skb->data, the extension bitmap length exceeds 32 when decoding ras message then uses the length to make a shift operation. It will change into negative after several loop. UBSAN load could detect a negative shift as an undefined behaviour and reports exception. So we add the protection to avoid the length exceeding 32. Or else it will return out of range error and stop decoding.

Patch / fix

  • Linux Linux 4.19.310, 5.4.272, 5.10.213, 5.15.152, 6.1.82, 6.6.22, 6.7.10, 6.8
  • Siemens SIMATIC S7-1500 TM MFP - GNU/Linux subsystem V1.1.1
  • linux Debian 12 6.1.82-1
  • linux Debian 14, Debian 13 6.7.12-1

debian advisories DEBIAN-CVE-2024-26851

  • linux Ubuntu 20.04 LTS 5.4.0-189.209
  • linux Ubuntu 22.04 LTS 5.15.0-112.122
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1128.138
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1063.69
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1132.141
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1062.70
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1060.66
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1075.80

ubuntu advisories UBUNTU-CVE-2024-26851

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-rt RHEL 8 4.18.0-553.27.1.rt7.368.el8_10
  • kernel-rt-kvm RHEL 8 4.18.0-553.27.1.rt7.368.el8_10
  • kernel-rt-core RHEL 8 4.18.0-553.27.1.rt7.368.el8_10
  • kernel-rt-modules RHEL 8 4.18.0-553.27.1.rt7.368.el8_10
  • kernel-rt-debug-kvm RHEL 8 4.18.0-553.27.1.rt7.368.el8_10
  • kernel-rt-debug-core RHEL 8 4.18.0-553.27.1.rt7.368.el8_10
  • kernel-rt-debug-modules RHEL 8 4.18.0-553.27.1.rt7.368.el8_10
  • kernel-rt-modules-extra RHEL 8 4.18.0-553.27.1.rt7.368.el8_10

red hat advisories RHSA-2025:3215RHSA-2024:8870RHSA-2024:8856RHSA-2024:6993

  • 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-2024:3252-1SUSE-SU-2024:3251-1

  • kernel AlmaLinux 8 4.18.0-553.27.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.27.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.27.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.27.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.27.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.27.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.27.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.27.1.el8_10

almalinux advisories ALSA-2024:8856ALSA-2024:8870

  • kernel-rt Rocky Linux 8 4.18.0-553.27.1.rt7.368.el8_10
  • kernel Rocky Linux 8 4.18.0-553.27.1.el8_10

rocky linux advisories RLSA-2024:8870RLSA-2024:8856

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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-2024-26851 updated cvss 5.5

kernel: netfilter: nf_conntrack_h323: Add protection for bmp length out of range

  • Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 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.9.4) libperf 5.14.0-427.61.1.el9_4, kernel-debuginfo-common-s390x 5.14.0-427.61.1.el9_4, kernel-debuginfo-common-x86_64 5.14.0-427.61.1.el9_4, kernel-debuginfo-common-aarch64 5.14.0-427.61.1.el9_4, kernel-debuginfo-common-ppc64le 5.14.0-427.61.1.el9_4 Red Hat Enterprise Linux AppStream EUS (v.9.4) rv 5.14.0-427.61.1.el9_4, perf 5.14.0-427.61.1.el9_4, rtla 5.14.0-427.61.1.el9_4, kernel-devel-matched 5.14.0-427.61.1.el9_4, kernel-64k-devel-matched 5.14.0-427.61.1.el9_4, kernel-debug-devel-matched 5.14.0-427.61.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:3215
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.27.1.el8_10, kernel 4.18.0-553.27.1.el8_10, bpftool 4.18.0-553.27.1.el8_10, kernel-core 4.18.0-553.27.1.el8_10, kernel-tools 4.18.0-553.27.1.el8_10, python3-perf 4.18.0-553.27.1.el8_10, +15 more
    fixed: vendor fix RHSA-2024:8856
  • 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.9.4) bpftool 7.3.0-427.61.1.el9_4, kernel 5.14.0-427.61.1.el9_4, kernel-64k 5.14.0-427.61.1.el9_4, kernel-core 5.14.0-427.61.1.el9_4, kernel-tools 5.14.0-427.61.1.el9_4, python3-perf 5.14.0-427.61.1.el9_4, +28 more
    fixed: vendor fix RHSA-2025:3215
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.27.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.27.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.27.1.el8_10
    fixed: vendor fix RHSA-2024:8856
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-kvm 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-core 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-modules 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-debug-kvm 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-debug-core 4.18.0-553.27.1.rt7.368.el8_10, +4 more
    fixed: vendor fix RHSA-2024:8870
show 3 more
  • Red Hat Enterprise Linux Real Time EUS (v.9.4) kernel-rt 5.14.0-427.61.1.el9_4, kernel-rt-core 5.14.0-427.61.1.el9_4, kernel-rt-modules 5.14.0-427.61.1.el9_4, kernel-rt-debug-core 5.14.0-427.61.1.el9_4, kernel-rt-modules-core 5.14.0-427.61.1.el9_4, kernel-rt-debug-modules 5.14.0-427.61.1.el9_4, +4 more Red Hat Enterprise Linux Real Time for NFV EUS (v.9.4) kernel-rt 5.14.0-427.61.1.el9_4, kernel-rt-kvm 5.14.0-427.61.1.el9_4, kernel-rt-core 5.14.0-427.61.1.el9_4, kernel-rt-modules 5.14.0-427.61.1.el9_4, kernel-rt-debug-kvm 5.14.0-427.61.1.el9_4, kernel-rt-debug-core 5.14.0-427.61.1.el9_4, +6 more
    fixed: vendor fix RHSA-2025:3215
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-core 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-modules 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-debug-core 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-debug-modules 4.18.0-553.27.1.rt7.368.el8_10, kernel-rt-modules-extra 4.18.0-553.27.1.rt7.368.el8_10, +2 more
    fixed: vendor fix RHSA-2024:8870
  • 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
    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 SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
2y ago

Exploit prediction

0.74% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 S7-1500 TM MFP - GNU/Linux subsystem

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel 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.