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Vulnerability · Published Mar 18, 2026 · Assigned by Linux

CVE-2026-23247tcp: secure_seq: add back ports to TS offset

Medium 5.5

In plain English

A medium-severity security flaw 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 0.2% (higher than 7% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.2%top 93.4% 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: tcp: secure_seq: add back ports to TS offset This reverts 28ee1b746f49 ("secure_seq: downgrade to per-host timestamp offsets") tcp_tw_recycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie side-channel that can be fixed in multiple ways. One of them is to bring back TCP ports in TS offset randomization. As a bonus, we perform a single siphash() computation to provide both an ISN and a TS offset.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12linuxno fix listedDEBIAN-CVE-2026-23247
Debian:13linux6.12.94-1DEBIAN-CVE-2026-23247
Debian:14linux6.19.8-1DEBIAN-CVE-2026-23247
Ubuntu:22.04:LTSlinuxno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinuxno fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linuxno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-allwinner-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-awsno fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linux-awsno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-aws-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-aws-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-aws-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-aws-6.2no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-aws-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-aws-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azureno fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linux-azureno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azure-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azure-6.11no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azure-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azure-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azure-6.2no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azure-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azure-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azure-fdeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linux-azure-fdeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azure-fde-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azure-fde-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azure-fde-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azure-fde-6.2no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-azure-fde-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azure-nvidiano fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-azure-nvidia-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-gcpno fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linux-gcpno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-gcp-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-gcp-6.11no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-gcp-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-gcp-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-gcp-6.2no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-gcp-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-gcp-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-gkeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-gkeopno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-hwe-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-hwe-6.11no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-hwe-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-hwe-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-hwe-6.2no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-hwe-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-hwe-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-ibmno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-ibm-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-intel-iot-realtimeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-intel-iotgno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-kvmno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-lowlatencyno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-lowlatency-hwe-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-lowlatency-hwe-6.11no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.2no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-lowlatency-hwe-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-nvidiano fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-nvidia-6.11no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-nvidia-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-nvidia-6.2no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-nvidia-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-nvidia-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-nvidia-lowlatencyno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-nvidia-tegrano fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-nvidia-tegra-igxno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-oem-5.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-oem-6.0no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-oem-6.1no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-oem-6.11no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-oem-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-oem-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-oem-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-oem-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-oracleno fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linux-oracleno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-oracle-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-oracle-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-oracle-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-oracle-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-raspino fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linux-raspino fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-raspi-realtimeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-realtimeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linux-realtimeno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-riscvno fix listedUBUNTU-CVE-2026-23247
Ubuntu:25.10linux-riscvno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-riscv-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-riscv-6.14no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-riscv-6.17no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-riscv-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-riscv-6.8no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-starfive-5.19no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-starfive-6.2no fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-starfive-6.5no fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-vmwareno fix listedUBUNTU-CVE-2026-23247
Ubuntu:24.04:LTSlinux-xilinxno fix listedUBUNTU-CVE-2026-23247
Ubuntu:22.04:LTSlinux-xilinx-zynqmpno fix listedUBUNTU-CVE-2026-23247

Affected products (as reported)

VendorProductVersions
Linux Linux 28ee1b746f493b7c62347d714f58fbf4f70df4f0 – before 025f532d8c5cfac77845e50daab7f478b360f2ac28ee1b746f493b7c62347d714f58fbf4f70df4f0 – before e873e8c16b2fb743a381a9e59c108e63512301ec28ee1b746f493b7c62347d714f58fbf4f70df4f0 – before 5da5662181ef8a251e3ba564903002c2e87de45228ee1b746f493b7c62347d714f58fbf4f70df4f0 – before eae2f14ab2efccdb7480fae7d42c4b0116ef880528ee1b746f493b7c62347d714f58fbf4f70df4f0 – before 46e5b0d7cf55821527adea471ffe52a5afbd9caf28ee1b746f493b7c62347d714f58fbf4f70df4f0 – before 165573e41f2f66ef98940cf65f838b2cb575d9d1443fac9f2618b93cbc5ab068dc594530236b3a234.10.14 – before 4.11
Linux Linux 4.11

References