CVE-2026-45889

MEDIUMNVD 5.55.5—
EchelonGraph scoreMEDIUM confidence

Score 5.5 from GitHub Security Advisory published 2026-05-27. NVD baseline CVSS 5.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
5.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 5.5Exploit: None knownExposed: 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:

mptcp: do not account for OoO in mptcp_rcvbuf_grow()

MPTCP-level OoOs are physiological when multiple subflows are active concurrently and will not cause retransmissions nor are caused by drops.

Accounting for them in mptcp_rcvbuf_grow() causes the rcvbuf slowly drifting towards tcp_rmem[2].

Remove such accounting. Note that subflows will still account for TCP-level OoO when the MPTCP-level rcvbuf is propagated.

This also closes a subtle and very unlikely race condition with rcvspace init; active sockets with user-space holding the msk-level socket lock, could complete such initialization in the receive callback, after that the first OoO data reaches the rcvbuf and potentially triggering a divide by zero Oops.

CVSS v3
5.5
EG Score
5.5(medium)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity55% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
5%
KEV
Not listed

Published

May 27, 2026

Last Modified

June 25, 2026

Advisory Details (3)

Auto-updated Jun 25, 2026
No patch confirmed yet.
generic

mptcp: do not account for OoO in mptcp_rcvbuf_grow() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/fb7bf00b04a6b48859f52035d4e745848c2b4c79
generic

mptcp: do not account for OoO in mptcp_rcvbuf_grow() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6b329393502e5857662b851a13f947209c588587
generic

mptcp: do not account for OoO in mptcp_rcvbuf_grow() - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/400ee4854adef1e4983812a3decf6717ea020136

Vendor Advisories for CVE-2026-45889(1)

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 @ 6.18.14—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.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 41× 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. 2026-07-27 14:13 UTCEPSS rescore
  2. 2026-07-27 12:21 UTCEG score recompute
  3. 2026-07-27 12:21 UTCGHSA enrichment
  4. 2026-07-26 14:54 UTCEPSS rescore
  5. 2026-07-26 14:54 UTCEPSS rescore
  6. 2026-07-26 06:12 UTCOSV refresh
  7. 2026-07-25 14:18 UTCEPSS rescore
  8. 2026-07-24 14:17 UTCEPSS rescore
  9. 2026-07-23 14:18 UTCEPSS rescore
  10. 2026-07-23 03:16 UTCEG score recompute
  11. 2026-07-22 14:08 UTCEPSS rescore
  12. 2026-07-21 15:24 UTCEPSS rescore
  13. 2026-07-20 17:08 UTCEPSS rescore
  14. 2026-07-19 14:31 UTCEPSS rescore
  15. 2026-07-19 02:29 UTCEPSS rescore
  16. 2026-07-18 10:04 UTCEPSS rescore
  17. 2026-07-16 17:03 UTCEPSS rescore
  18. 2026-07-15 16:57 UTCEPSS rescore
  19. 2026-07-15 02:00 UTCEPSS rescore
  20. 2026-07-13 22:30 UTCEPSS rescore
  21. 2026-07-13 06:13 UTCEPSS rescore
  22. 2026-07-12 05:46 UTCEPSS rescore
  23. 2026-07-11 08:27 UTCEPSS rescore
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-09 00:24 UTCGHSA enrichment
Show 75 more
  1. 2026-07-08 15:16 UTCEPSS rescore
  2. 2026-07-07 13:46 UTCEPSS rescore
  3. 2026-07-06 16:27 UTCEPSS rescore
  4. 2026-07-06 02:23 UTCEPSS rescore
  5. 2026-07-05 02:30 UTCEPSS rescore
  6. 2026-07-04 06:31 UTCEPSS rescore
  7. 2026-07-01 15:07 UTCEPSS rescore
  8. 2026-07-01 11:37 UTCGHSA enrichment
  9. 2026-06-30 23:22 UTCEPSS rescore
  10. 2026-06-29 19:49 UTCGHSA enrichment
  11. 2026-06-29 14:06 UTCEPSS rescore
  12. 2026-06-29 14:06 UTCEPSS rescore
  13. 2026-06-28 21:23 UTCGHSA enrichment
  14. 2026-06-28 14:07 UTCEPSS rescore
  15. 2026-06-28 04:56 UTCEPSS rescore
  16. 2026-06-28 04:56 UTCEPSS rescore
  17. 2026-06-27 21:15 UTCEG score recompute▲ 5.50
  18. 2026-06-27 21:15 UTCGHSA enrichment
  19. 2026-06-27 03:08 UTCEPSS rescore
  20. 2026-06-25 21:50 UTCNVD updateCVSS v3 → 5.5 · severity → MEDIUM
  21. 2026-06-25 13:49 UTCEPSS rescore
  22. 2026-06-25 01:47 UTCGHSA enrichment
  23. 2026-06-24 14:05 UTCEPSS rescore
  24. 2026-06-23 21:33 UTCEPSS rescore
  25. 2026-06-23 21:33 UTCEPSS rescore
  26. 2026-06-22 14:25 UTCEPSS rescore
  27. 2026-06-22 14:25 UTCEPSS rescore
  28. 2026-06-21 14:56 UTCEPSS rescore
  29. 2026-06-21 14:56 UTCEPSS rescore
  30. 2026-06-21 01:59 UTCEPSS rescore
  31. 2026-06-21 01:59 UTCEPSS rescore
  32. 2026-06-19 19:26 UTCEPSS rescore
  33. 2026-06-19 19:26 UTCEPSS rescore
  34. 2026-06-18 17:52 UTCEPSS rescore
  35. 2026-06-18 17:52 UTCEPSS rescore
  36. 2026-06-17 21:25 UTCGHSA enrichment
  37. 2026-06-17 17:53 UTCEPSS rescore
  38. 2026-06-16 17:52 UTCEPSS rescore
  39. 2026-06-15 17:49 UTCEPSS rescore
  40. 2026-06-15 02:06 UTCGHSA enrichment
  41. 2026-06-13 23:00 UTCEPSS rescore
  42. 2026-06-12 23:12 UTCEPSS rescore
  43. 2026-06-12 23:12 UTCEPSS rescore
  44. 2026-06-12 06:49 UTCGHSA enrichment
  45. 2026-06-11 14:00 UTCEPSS rescore
  46. 2026-06-10 22:18 UTCEPSS rescore
  47. 2026-06-10 13:22 UTCEPSS rescore
  48. 2026-06-10 13:22 UTCEPSS rescore
  49. 2026-06-09 11:32 UTCGHSA enrichment
  50. 2026-06-08 14:17 UTCEPSS rescore
  51. 2026-06-08 14:17 UTCEPSS rescore
  52. 2026-06-07 15:25 UTCEPSS rescore
  53. 2026-06-07 15:25 UTCEPSS rescore
  54. 2026-06-06 16:16 UTCGHSA enrichment
  55. 2026-06-06 13:47 UTCEPSS rescore
  56. 2026-06-06 13:47 UTCEPSS rescore
  57. 2026-06-05 22:47 UTCEPSS rescore
  58. 2026-06-05 06:10 UTCEPSS rescore
  59. 2026-06-05 06:10 UTCEPSS rescore
  60. 2026-06-04 13:12 UTCEPSS rescore
  61. 2026-06-04 13:12 UTCEPSS rescore
  62. 2026-06-03 20:59 UTCGHSA enrichment
  63. 2026-06-02 20:13 UTCEPSS rescore
  64. 2026-06-01 13:52 UTCEPSS rescore
  65. 2026-06-01 13:52 UTCEPSS rescore
  66. 2026-06-01 01:42 UTCGHSA enrichment
  67. 2026-05-31 22:30 UTCEPSS rescore
  68. 2026-05-31 22:30 UTCEPSS rescore
  69. 2026-05-31 00:16 UTCEPSS rescore
  70. 2026-05-31 00:16 UTCEPSS rescore
  71. 2026-05-29 13:44 UTCEPSS rescore
  72. 2026-05-29 13:44 UTCEPSS rescore
  73. 2026-05-28 13:44 UTCEPSS rescore
  74. 2026-05-28 13:44 UTCEPSS rescore
  75. 2026-05-27 14:18 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-45889?
CVE-2026-45889 is a medium vulnerability published on May 27, 2026. In the Linux kernel, the following vulnerability has been resolved: mptcp: do not account for OoO in mptcprcvbufgrow() MPTCP-level OoOs are physiological when multiple subflows are active concurrently and will not cause retransmissions nor are caused by drops. Accounting for them in…
When was CVE-2026-45889 disclosed?
CVE-2026-45889 was first published in the National Vulnerability Database on May 27, 2026, with the most recent update on June 25, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-45889 actively exploited?
CVE-2026-45889 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 95.0% of all scored CVEs.
What is the CVSS score of CVE-2026-45889?
CVE-2026-45889 has a CVSS v3 base score of 5.5 (NVD).
How do I remediate CVE-2026-45889?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-45889, 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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