PT-2026-26050 · Linux · Linux Kernel

Zhouyan Deng · Published 2026-01-01 · Updated 2026-04-20 · CVE-2026-23247

Positive Technologies (AI Summary)

CVSS v2.0

4.6

Medium

Base vector

AV:L/AC:L/Au:S/C:N/I:N/A:C

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

OESA-2026-1946

OESA-2026-1947

OESA-2026-1948

Affected Products

Linux Kernel

References · 40

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23247.json · Exploit
• https://osv.dev/vulnerability/ROOT-OS-UBUNTU-2204-CVE-2026-23247 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-31399 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-23247 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-23440 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-31408 · Security Note
• https://osv.dev/vulnerability/OESA-2026-1947 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-23247 · Security Note
• https://osv.dev/vulnerability/OESA-2026-1946 · Vendor Advisory
• https://osv.dev/vulnerability/ROOT-OS-UBUNTU-2404-CVE-2026-23247 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-23247 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-23247 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-23461 · Security Note
• https://osv.dev/vulnerability/OESA-2026-1948 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-23389 · Security Note