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Vulnerability · Published Apr 3, 2026 · Assigned by Linux

CVE-2026-23456netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case

High 8.2

In plain English

A high-severity out-of-bounds read in Linux from Linux. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.5%top 54.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case In decode_int(), the CONS case calls get_bits(bs, 2) to read a length value, then calls get_uint(bs, len) without checking that len bytes remain in the buffer. The existing boundary check only validates the 2 bits for get_bits(), not the subsequent 1-4 bytes that get_uint() reads. This allows a malformed H.323/RAS packet to cause a 1-4 byte slab-out-of-bounds read. Add a boundary check for len bytes after get_bits() and before get_uint().

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linux6.1.170-1DEBIAN-CVE-2026-23456
Debian:13linux6.12.85-1DEBIAN-CVE-2026-23456
Debian:14linux6.19.10-1DEBIAN-CVE-2026-23456
Ubuntu:22.04:LTSlinux5.15.0-186.196UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux6.8.0-136.136UBUNTU-CVE-2026-23456
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-aws5.15.0-1112.119UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-aws6.8.0-1061.64UBUNTU-CVE-2026-23456
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-aws-6.86.8.0-1061.64~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure5.15.0-1117.126UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-azure6.8.0-1063.71UBUNTU-CVE-2026-23456
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure-6.86.8.0-1063.71~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure-fde5.15.0-1117.126UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-azure-fde6.8.0-1062.69UBUNTU-CVE-2026-23456
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-azure-fde-6.86.8.0-1062.69~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-gcp5.15.0-1112.122UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-gcp6.8.0-1064.72UBUNTU-CVE-2026-23456
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-gcp-6.86.8.0-1064.72~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-gke5.15.0-1108.114UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-gke6.8.0-1059.67UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-gkeop5.15.0-1095.103UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-gkeop6.8.0-1046.50UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-hwe-6.86.8.0-136.136~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-ibm5.15.0-1106.110UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-ibm6.8.0-1061.62UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-ibm-6.86.8.0-1061.62~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-intel-iotg5.15.0-1107.113UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-kvm5.15.0-1104.109UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-lowlatency5.15.0-184.194UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-lowlatency6.8.0-136.136.2UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.86.8.0-136.136.2~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-nvidia5.15.0-1107.108UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-nvidia6.8.0-1059.62UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-nvidia-6.86.8.0-1059.62~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-nvidia-lowlatency6.8.0-1059.62.1UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-nvidia-tegra5.15.0-1064.66UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-nvidia-tegra6.8.0-1030.31UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-nvidia-tegra-igx5.15.0-1053.53UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-oracle5.15.0-1109.115UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-oracle6.8.0-1058.61UBUNTU-CVE-2026-23456
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-oracle-6.86.8.0-1058.61~22.04.1UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-raspi5.15.0-1106.109UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-raspi6.8.0-1061.65UBUNTU-CVE-2026-23456
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-23456
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-23456
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-riscv-6.86.8.0-136.136~22.04.3UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-vmware6.8.0-1008.8UBUNTU-CVE-2026-23456
Ubuntu:24.04:LTSlinux-xilinx6.8.0-1033.34UBUNTU-CVE-2026-23456
Ubuntu:22.04:LTSlinux-xilinx-zynqmp5.15.0-1075.79UBUNTU-CVE-2026-23456

Affected products (as reported)

VendorProductVersions
Linux Linux 5e35941d990123f155b02d5663e51a24f816b6f3 – before a2cd54b9348e485d338b3c132338a4410c99afaf5e35941d990123f155b02d5663e51a24f816b6f3 – before c95dc674ebf01ecfb40388b6facfc89b81fed3b75e35941d990123f155b02d5663e51a24f816b6f3 – before 41b417ff73a24b2c68134992cc44c88db27f482d5e35941d990123f155b02d5663e51a24f816b6f3 – before 52235bf88159a1ef16434ab49e47e99c8a09ab205e35941d990123f155b02d5663e51a24f816b6f3 – before 774a434f8c9c8602a976b2536f65d0172a07f4d25e35941d990123f155b02d5663e51a24f816b6f3 – before 6bce72daeccca9aa1746e92d6c3d4784e71f2ebb5e35941d990123f155b02d5663e51a24f816b6f3 – before fb6c3596823ec5dd09c2123340330d7448f51a595e35941d990123f155b02d5663e51a24f816b6f3 – before 1e3a3593162c96e8a8de48b1e14f60c3b57fca8a
Linux Linux 2.6.17

Weakness: CWE-125 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

References