PT-2026-26050 · Linux · Linux Kernel

Zhouyan Deng · Published 2026-01-01 · Updated 2026-05-26 · CVE-2026-23247

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The Linux kernel addresses an issue where off-path TCP source port leakage could occur via a SYN cookie side-channel. The resolution involves reintroducing TCP ports into the timestamp offset randomization process, effectively reverting a previous change. This is achieved through a single siphash() computation to generate both an Initial Sequence Number (ISN) and a timestamp offset. The issue was reported by Zhouyan Deng.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Use of Insufficiently Random Values

Weakness Enumeration

CWE-330

Related Identifiers

BDU:2026-04643

CVE-2026-23247

ECHO-158A-27E7-5170

OESA-2026-1946

OESA-2026-1947

OESA-2026-1948

Affected Products

Linux Kernel

References · 42

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23247.json · Exploit
• https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf · Patch
• https://osv.dev/vulnerability/OESA-2026-1947 · Vendor Advisory
• https://osv.dev/vulnerability/BELL-CVE-2026-23247 · Vendor Advisory
• https://git.kernel.org/stable/c/165573e41f2f66ef98940cf65f838b2cb575d9d1 · Patch
• https://osv.dev/vulnerability/OESA-2026-1946 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-23389 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-31393 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-23440 · Security Note
• https://osv.dev/vulnerability/OESA-2026-1948 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-23247 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-23444 · Security Note
• https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805 · Patch
• https://cve.org/CVERecord?id=CVE-2026-23247 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-23247 · Vendor Advisory