Exposure of sensitive information to an unauthorized actor in Linux kernel - CVE-2026-23247

Vulnerability identifier: #VU124203

CSH Severity: Medium

CVSS v4 BT: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2026-23247

CWE-ID: CWE-200

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to improper output neutralization in the TCP sequence number generation mechanism when handling SYN cookies. A remote attacker can send specially crafted TCP connection requests to disclose sensitive information.

The attacker can exploit the side-channel to infer TCP source ports, enabling off-path attacks that leak information about connection parameters.

Linux kernel
Debian Linux
openEuler
python3-perf-debuginfo
kernel
bpftool
bpftool-debuginfo
kernel-debuginfo
kernel-debugsource
kernel-devel
kernel-headers
kernel-tools
kernel-tools-debuginfo
kernel-tools-devel
perf
perf-debuginfo
python3-perf
kernel-source
kernel-extra-modules
linux (Debian package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
python3-perf-debuginfo - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
bpftool - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
bpftool-debuginfo - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-debuginfo - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-debugsource - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-devel - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-headers - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-tools - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-tools-debuginfo - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-tools-devel - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
perf - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
perf-debuginfo - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
python3-perf - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-source - addressed in versions 6.6.0-145.0.3.131, 6.6.0-145.0.3.143, 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
kernel-extra-modules - addressed in versions 6.6.0-145.0.3.144, 6.6.0-145.3.14.145
linux (Debian package) - update to 6.12.94-1

• https://git.kernel.org/stable/c/165573e41f2f66ef98940cf65f838b2cb575d9d1
• https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf
• https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805

• Exposure of sensitive information to an unauthorized actor in Linux kernel ipv6
• openEuler 24.03 LTS SP2 update for kernel
• openEuler 24.03 LTS SP1 update for kernel
• openEuler 24.03 LTS update for kernel
• openEuler 24.03 LTS SP3 update for kernel
• Debian update for linux