CVE-2026-23247
MediumIn 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.
CVSS 3.1 score
5.5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Affected versions
Linux kernel versions
4.10.14,
4.11
and later are affected. Fixed in
6.12.94,
6.18.17,
6.19.7,
7.0
and their respective stable series.
References
4 total-
Patch
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Patch
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Patch
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Frequently asked questions
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What is CVE-2026-23247?
CVE-2026-23247 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 4.10.14 onward and has been patched in 6.12.94, 6.18.17, 6.19.7 and others. CVE-2026-23247 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
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What is the CVSS score for CVE-2026-23247?
CVE-2026-23247 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. -
Is there a patch available for CVE-2026-23247?
Yes. CVE-2026-23247 has been patched. Fixed versions include 6.12.94, 6.18.17, 6.19.7 and others. If you are running Linux kernel 4.10.14 or later up to the fix versions, apply the relevant patch for your kernel branch.
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Is CVE-2026-23247 actively exploited?
No. CVE-2026-23247 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.