CVE-2026-23247
MediumCVSS 5.5Exploitation Probability (EPSS)
Low risk2th percentile - higher than 2% of all known CVEs
Summary
A vulnerability has been identified in the Linux kernel regarding TCP source port leakage via a SYN cookie side-channel. A fix has been implemented that brings back TCP ports to the timestamp offset randomization.
Risk Assessment
Organizations may be exposed to attacks that exploit TCP source port leakage, potentially leading to unauthorized access or data manipulation.
Recommendation
It is recommended to update the Linux kernel to the latest version to patch this vulnerability and minimize the risk associated with TCP protocol attacks.
Original NVD description (English source)
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.