CVE-2026-23247

CVE-2026-23247

Medium · published March 18, 2026

CVSS v3.1
5.5
EPSS
0%
Percentile
1.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.5 · MEDIUM
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00123 · 1.9th percentile
Published
2026-03-18T15:16Z
Affected products (9)
ProductVersionsFixed in
linux/linux_kernel> 4.11, < 6.18.176.18.17
linux/linux_kernel≥ 6.19, < 6.19.76.19.7
linux/linux_kernelall versions—
linux/linux_kernelall versions—
linux/linux_kernelall versions—
linux/linux_kernelall versions—
linux/linux_kernelall versions—
linux/linux_kernelall versions—
linux/linux_kernelall versions—
References (5)
https://git.kernel.org/stable/c/165573e41f2f66ef98940cf65f838b2cb575d9d1 · 416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf · 416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5da5662181ef8a251e3ba564903002c2e87de452 · 416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/e873e8c16b2fb743a381a9e59c108e63512301ec · 416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805 · 416baaa9-dc9f-4396-8d5f-8c081fb06d67
EPSS history
Timeline
  • 18 MAR 10:05Z
    tcp: secure_seq: add back ports to TS offset
    cvelistv5