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VulnerabilityPublished Updated

CVE-2026-23247: Linux kernel · tcp: secure_seq: add back ports to TS offset

Source GCVE Database

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Authoritative record:CVE-2026-23247· Medium

Not known to be exploited · CVSS 5.5 Medium · fixed in eae2f14ab2efccdb7480fae7d42c4b0116ef8805 : update Linux kernel when convenient.

Data as of 30 Oct 2026, 16:33 UTC

CVSS 3.1 base score
5.5Medium
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
Patch
Available – fixed in eae2f14ab2efccdb7480fae7d42c4b0116ef8805, e873e8c16b2fb743a381a9e59c108e63512301ec, 165573e41f2f66ef98940cf65f838b2cb575d9d1 +4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 18 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • >=4.10.14 <4.11
Fixed in
  • eae2f14ab2efccdb7480fae7d42c4b0116ef8805
  • e873e8c16b2fb743a381a9e59c108e63512301ec
  • 165573e41f2f66ef98940cf65f838b2cb575d9d1
  • 46e5b0d7cf55821527adea471ffe52a5afbd9caf
  • 025f532d8c5cfac77845e50daab7f478b360f2ac
  • 5da5662181ef8a251e3ba564903002c2e87de452
  • 4.11
LinuxLinuxAffected
  • =4.11
Fixed in–

Description

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.

References

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