CVE-2026-23247

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-03-18. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.5
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 5.5Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
5.5
EG Score
5.5(medium)
EPSS
2.0%
KEV
Not listed

Published

March 18, 2026

Last Modified

June 19, 2026

Advisory Details (4)

Auto-updated Jun 19, 2026
No patch confirmed yet.
generic

tcp: secure_seq: add back ports to TS offset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/eae2f14ab2efccdb7480fae7d42c4b0116ef8805
generic

tcp: secure_seq: add back ports to TS offset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5da5662181ef8a251e3ba564903002c2e87de452
generic

tcp: secure_seq: add back ports to TS offset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/46e5b0d7cf55821527adea471ffe52a5afbd9caf
generic

tcp: secure_seq: add back ports to TS offset - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/165573e41f2f66ef98940cf65f838b2cb575d9d1

Vendor Advisories for CVE-2026-23247(2)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
linuxKernel @ 6.18.17—osv

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Data Freshness Timeline

(refreshed 7× in last 7d / 42× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 16:57 UTCEPSS rescore
  3. 2026-07-13 22:30 UTCEPSS rescore
  4. 2026-07-13 06:13 UTCEPSS rescore
  5. 2026-07-13 06:13 UTCEPSS rescore
  6. 2026-07-11 08:27 UTCEPSS rescore
  7. 2026-07-09 19:10 UTCEPSS rescore
  8. 2026-07-08 15:15 UTCEPSS rescore
  9. 2026-07-08 15:15 UTCEPSS rescore
  10. 2026-07-07 13:46 UTCEPSS rescore
  11. 2026-07-06 16:27 UTCEPSS rescore
  12. 2026-07-06 16:27 UTCEPSS rescore
  13. 2026-07-06 02:23 UTCEPSS rescore
  14. 2026-07-06 02:23 UTCEPSS rescore
  15. 2026-07-05 02:30 UTCEPSS rescore
  16. 2026-07-04 06:31 UTCEPSS rescore
  17. 2026-07-04 06:31 UTCEPSS rescore
  18. 2026-07-01 15:06 UTCEPSS rescore
  19. 2026-07-01 15:06 UTCEPSS rescore
  20. 2026-06-30 23:22 UTCEPSS rescore
  21. 2026-06-30 23:22 UTCEPSS rescore
  22. 2026-06-29 14:06 UTCEPSS rescore
  23. 2026-06-29 06:02 UTCOSV refresh
  24. 2026-06-28 14:07 UTCEPSS rescore
  25. 2026-06-28 14:07 UTCEPSS rescore
Show 73 more
  1. 2026-06-27 03:08 UTCEPSS rescore
  2. 2026-06-25 13:49 UTCEPSS rescore
  3. 2026-06-25 13:49 UTCEPSS rescore
  4. 2026-06-23 21:33 UTCEPSS rescore
  5. 2026-06-23 21:32 UTCEPSS rescore
  6. 2026-06-22 14:25 UTCEPSS rescore
  7. 2026-06-22 14:25 UTCEPSS rescore
  8. 2026-06-21 14:56 UTCEPSS rescore
  9. 2026-06-21 14:56 UTCEPSS rescore
  10. 2026-06-21 01:59 UTCEPSS rescore
  11. 2026-06-21 01:59 UTCEPSS rescore
  12. 2026-06-19 19:25 UTCEPSS rescore
  13. 2026-06-19 19:25 UTCEPSS rescore
  14. 2026-06-18 17:52 UTCEPSS rescore
  15. 2026-06-17 17:53 UTCEPSS rescore
  16. 2026-06-17 17:53 UTCEPSS rescore
  17. 2026-06-16 17:52 UTCEPSS rescore
  18. 2026-06-15 17:48 UTCEPSS rescore
  19. 2026-06-14 23:18 UTCEPSS rescore
  20. 2026-06-13 23:00 UTCEPSS rescore
  21. 2026-06-13 23:00 UTCEPSS rescore
  22. 2026-06-11 23:50 UTCEG score recompute
  23. 2026-06-11 23:50 UTCGHSA enrichment
  24. 2026-06-11 14:00 UTCEPSS rescore
  25. 2026-06-10 22:18 UTCEPSS rescore
  26. 2026-06-10 15:46 UTCEG score recompute
  27. 2026-06-10 15:46 UTCGHSA enrichment
  28. 2026-06-10 13:22 UTCEPSS rescore
  29. 2026-06-09 16:35 UTCEG score recompute
  30. 2026-06-09 16:35 UTCGHSA enrichment
  31. 2026-06-08 14:17 UTCEPSS rescore
  32. 2026-06-08 14:17 UTCEPSS rescore
  33. 2026-06-07 15:25 UTCEPSS rescore
  34. 2026-06-07 15:24 UTCEPSS rescore
  35. 2026-06-07 14:26 UTCEG score recompute
  36. 2026-06-07 14:26 UTCGHSA enrichment
  37. 2026-06-06 13:47 UTCEPSS rescore
  38. 2026-06-06 13:47 UTCEPSS rescore
  39. 2026-06-06 13:47 UTCEPSS rescore
  40. 2026-06-05 22:47 UTCEPSS rescore
  41. 2026-06-05 06:10 UTCEPSS rescore
  42. 2026-06-05 06:10 UTCEPSS rescore
  43. 2026-06-04 13:12 UTCEPSS rescore
  44. 2026-06-04 13:12 UTCEPSS rescore
  45. 2026-06-04 13:12 UTCEPSS rescore
  46. 2026-06-03 22:09 UTCOSV refresh
  47. 2026-06-02 20:13 UTCEPSS rescore
  48. 2026-06-02 20:13 UTCEPSS rescore
  49. 2026-06-01 13:51 UTCEPSS rescore
  50. 2026-06-01 13:51 UTCEPSS rescore
  51. 2026-06-01 13:51 UTCEPSS rescore
  52. 2026-05-31 22:30 UTCEPSS rescore
  53. 2026-05-31 22:30 UTCEPSS rescore
  54. 2026-05-31 00:16 UTCEPSS rescore
  55. 2026-05-31 00:16 UTCEPSS rescore
  56. 2026-05-31 00:16 UTCEPSS rescore
  57. 2026-05-29 13:44 UTCEPSS rescore
  58. 2026-05-29 13:44 UTCEPSS rescore
  59. 2026-05-28 13:44 UTCEPSS rescore
  60. 2026-05-28 13:44 UTCEPSS rescore
  61. 2026-05-28 13:44 UTCEPSS rescore
  62. 2026-05-27 13:40 UTCEPSS rescore
  63. 2026-05-27 13:40 UTCEPSS rescore
  64. 2026-05-27 13:40 UTCEPSS rescore
  65. 2026-05-26 13:44 UTCEPSS rescore
  66. 2026-05-26 13:44 UTCEPSS rescore
  67. 2026-05-26 07:18 UTCEPSS rescore
  68. 2026-05-26 07:18 UTCEPSS rescore
  69. 2026-05-26 07:18 UTCEPSS rescore
  70. 2026-05-22 21:16 UTCEPSS rescore
  71. 2026-05-21 22:43 UTCEPSS rescore
  72. 2026-05-21 18:45 UTCEG score recompute
  73. 2026-05-21 18:45 UTCGHSA enrichment

Related CVEs(same product)

Frequently asked(5)

What is CVE-2026-23247?
CVE-2026-23247 is a medium vulnerability published on March 18, 2026. 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") tcptwrecycle went away in 2017. Zhouyan Deng reported off-path TCP source port leakage via SYN cookie…
When was CVE-2026-23247 disclosed?
CVE-2026-23247 was first published in the National Vulnerability Database on March 18, 2026, with the most recent update on June 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23247 actively exploited?
CVE-2026-23247 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 2.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-23247?
CVE-2026-23247 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-23247?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23247, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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