CVE-2026-63867

HIGHPre-NVD 8.28.2
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

Score 8.2 from GitHub Security Advisory (severity: HIGH) published 2026-07-19. The CNA's CVSS baseline 8.2; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: the CNA's CVSS, EPSS, GitHub Security Advisory
Trending — 4 sources updated this week
8.2EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 8.2Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In the Linux kernel, the following vulnerability has been resolved:

mptcp: close TOCTOU race while computing rcv_wnd

The MPTCP output path access locklessly the MPTCP-level ack_seq in multiple times, using possibly different values for the data_ack in the DSS option and to compute the announced rcv wnd for the same packet.

Refactor the cote to avoid inconsistencies which may confuse the peer. Also ensure that the MPTCP level rcv wnd is updated only when the egress packet actually contains a DSS ack.

CVSS v3
8.2
EG Score
8.2HIGHmedium confidence
EG Risk
37
EG Risk 37/100

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 (value × EchelonGraph’s weight)
Severity82% × 45%
The EG Score, 8.2 of 10.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's BOD 26-04 default: no one has published Automatable for this CVE, and CISA treats it as “no” for a CVE not in KEV.
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
25th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation none (no CISA value, KEV listing or exploit code on record) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). EchelonGraph holds no SSVC assessment of this CVE from CISA: none of these inputs is from Vulnrichment. EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 19, 2026

Last Modified

August 5, 2026

Advisory Details (7)

Auto-updated Jul 21, 2026
Patch available.
Web page

mptcp: close TOCTOU race while computing rcv_wnd - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/c4f4cf60797974873dbc8e100144682a6f2f861f
Web page

mptcp: close TOCTOU race while computing rcv_wnd - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/907ac6b1658e0277f979fcdfae2a753b495c1510
Web page

mptcp: close TOCTOU race while computing rcv_wnd - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8f4f0a157e8436a05bf8c3670b24dbc258911c43
Web page

mptcp: close TOCTOU race while computing rcv_wnd - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/8ab24fdebc369c0dfb90f82c1650b1e66662bb45
Web page

mptcp: close TOCTOU race while computing rcv_wnd - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/68364963e5baf03f16b4420292291f75c8f66497
Web page

mptcp: close TOCTOU race while computing rcv_wnd - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/3b8cbba7c0ed31189c89f90be247b8973ffa79ef
Web page

mptcp: close TOCTOU race while computing rcv_wnd - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/301a33fd590c408a05c5df800e0cc1e6a8a2f8f8

Vendor Advisories for CVE-2026-63867(1)

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

Patch Availability(23)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulinux-tools-gcp-edge (7.0.0-1011.11~24.04.1) @ noble2026-10-13ubuntu
ubuntulinux-tools-nvidia-hwe-24.04-edge (7.0.0-1018.18~24.04.1) @ noble2026-10-13ubuntu
ubuntulinux-tools-oracle-edge (7.0.0-1011.11~24.04.1) @ noble2026-10-13ubuntu
ubuntulinux-tools-oem-7.0 (7.0.0-1013.13) @ resolute2026-10-13ubuntu
ubuntulinux-tools-raspi-realtime-7.0 (7.0.0-1019.19) @ resolute2026-10-13ubuntu
ubuntulinux-tools-ibm-7.0 (7.0.0-1013.13) @ resolute2026-10-13ubuntu
ubuntulinux-tools-nvidia-hwe-26.04 (7.0.0-2018.18) @ resolute2026-10-13ubuntu
ubuntulinux-tools-nvidia-hwe-24.04-edge (7.0.0-1018.18) @ resolute2026-10-13ubuntu
ubuntulinux-tools-oracle-7.0 (7.0.0-1011.11) @ resolute2026-10-13ubuntu
ubuntulinux-tools-azure-edge (7.0.0-1014.14~24.04.1) @ noble2026-10-13ubuntu
ubuntulinux-tools-oracle-lts-24.04 (6.8.0-1063.66) @ noble2026-10-13ubuntu
ubuntulinux-tools-gcp-lts-22.04 (5.15.0.1118.115) @ jammy2026-10-13ubuntu
ubuntulinux-xilinx-zynqmp-tools-5.15.0-1080 (5.15.0-1080.84) @ jammy2026-10-13ubuntu
ubuntulinux-tools-azure-lts-24.04 (6.8.0-1070.78) @ noble2026-10-13ubuntu
ubuntulinux-tools-gcp-edge (5.15.0.1118.128~20.04.1) @ focal2026-10-13ubuntu
ubuntulinux-virtual-hwe-26.04-edge (7.0.0-31.31) @ resolute2026-10-13ubuntu
ubuntulinux-tools-ibm-edge (6.8.0-1066.67~22.04.1) @ jammy2026-10-13ubuntu
ubuntulinux-tools-oracle-edge (5.15.0.1114.120~20.04.1) @ focal2026-10-13ubuntu
ubuntulinux-virtual-6.8 (6.8.0-146.146) @ noble2026-10-13ubuntu
ubuntulinux-tools-nvidia-tegra-rt-6.8 (6.8.0-1036.39) @ noble2026-10-13ubuntu
ubuntulinux-tools-gcp-fips-6.8 (6.8.0-1070.78+fips1) @ noble2026-10-13ubuntu
ubuntulinux-tools-nvidia-lowlatency-5.15 (5.15.0.1112.112) @ jammy2026-10-13ubuntu
ubuntulinux-tools-gcp-lts-24.04 (6.8.0-1070.78) @ noble2026-10-13ubuntu

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.

Affected Packages

(3 across 3 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.1.106-1 ... 6.1.99-1 (53 versions)
  • every version up to 6.1.176-1: fixed in 6.1.176-1
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.38-1 ... 6.12.94-1~bpo12+1 (27 versions)
  • every version up to 6.12.94-1: fixed in 6.12.94-1
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
linux6.12.100-1 ... 7.0.9-1~bpo13+1 (146 versions)
  • every version up to 7.0.13-1: fixed in 7.0.13-1
—

All Vendor Advisories

(23)

Data Freshness Timeline

(refreshed 14× in last 7d / 49× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 322 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 222 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  2. 2026-10-13 11:50 UTCEG score recompute
  3. 2026-10-13 11:50 UTCVendor advisory
  4. 2026-10-13 11:50 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  5. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  6. 2026-10-12 15:48 UTCEG score recompute
  7. 2026-10-11 19:33 UTCEG score recompute
  8. 2026-10-11 16:48 UTCEG score recompute
  9. 2026-10-11 14:09 UTCEG score recompute
  10. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  11. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  12. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  13. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  14. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  15. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  16. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  17. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  18. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  19. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.3% · 25th percentile
  20. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  21. 2026-10-01 09:06 UTCEG score recompute
  22. 2026-10-01 09:06 UTCVendor advisory
  23. 2026-10-01 09:06 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  24. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  25. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 24th percentile
Show 75 more
  1. 2026-09-28 07:36 UTCEG score recompute
  2. 2026-09-28 07:36 UTCVendor advisory
  3. 2026-09-28 07:35 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  4. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  5. 2026-09-24 04:16 UTCEG score recompute
  6. 2026-09-24 04:16 UTCVendor advisory
  7. 2026-09-24 04:16 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  8. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.6% · 47th percentile
  9. 2026-09-23 02:11 UTCEG score recompute
  10. 2026-09-23 02:11 UTCVendor advisory
  11. 2026-09-23 02:11 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  12. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  13. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  14. 2026-09-18 04:24 UTCEG score recompute
  15. 2026-09-18 04:24 UTCVendor advisory
  16. 2026-09-18 04:24 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  17. 2026-09-17 10:02 UTCEG score recompute
  18. 2026-09-17 10:02 UTCVendor advisory
  19. 2026-09-17 10:01 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  20. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  21. 2026-09-16 13:09 UTCEG score recompute
  22. 2026-09-16 13:09 UTCVendor advisory
  23. 2026-09-16 13:09 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  24. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  25. 2026-09-14 04:20 UTCEG score recompute
  26. 2026-09-14 04:20 UTCVendor advisory
  27. 2026-09-14 04:20 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  28. 2026-09-13 16:14 UTCVendor advisory
  29. 2026-09-13 16:14 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  30. 2026-09-13 03:36 UTCEG score recompute
  31. 2026-09-13 03:36 UTCVendor advisory
  32. 2026-09-13 03:36 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  33. 2026-09-12 10:14 UTCVendor advisory
  34. 2026-09-12 10:14 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  35. 2026-09-11 19:42 UTCEG score recompute
  36. 2026-09-11 19:42 UTCVendor advisory
  37. 2026-09-11 19:42 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  38. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  39. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  40. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  41. 2026-09-07 23:42 UTCEG score recompute
  42. 2026-09-07 23:42 UTCVendor advisory
  43. 2026-09-07 23:41 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  44. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  45. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  46. 2026-09-06 13:05 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  47. 2026-09-05 20:13 UTCEG score recompute
  48. 2026-09-05 20:13 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  49. 2026-09-05 15:31 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  50. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  51. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.6% · 46th percentile
  52. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  53. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  54. 2026-08-31 03:47 UTCEG score recompute
  55. 2026-08-31 03:47 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  56. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  57. 2026-08-30 15:41 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  58. 2026-08-30 03:00 UTCEG score recompute
  59. 2026-08-30 03:00 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  60. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  61. 2026-08-28 21:42 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  62. 2026-08-28 01:44 UTCEG score recompute
  63. 2026-08-28 01:44 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  64. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  65. 2026-08-27 13:14 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  66. 2026-08-27 01:07 UTCEG score recompute
  67. 2026-08-27 01:07 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  68. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  69. 2026-08-26 12:58 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  70. 2026-08-26 00:52 UTCEG score recompute
  71. 2026-08-26 00:52 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  72. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.6% · 45th percentile
  73. 2026-08-25 12:47 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2
  74. 2026-08-25 00:41 UTCEG score recompute
  75. 2026-08-25 00:41 UTCGHSA enrichmentGHSA-wqpm-3qh2-7cxj · GitHub severity HIGH · GitHub CVSS 8.2

Frequently asked(5)

What is CVE-2026-63867?
CVE-2026-63867 is a high-severity vulnerability; its CVE record was published on July 19, 2026. In the Linux kernel, the following vulnerability has been resolved: mptcp: close TOCTOU race while computing rcv_wnd The MPTCP output path access locklessly the MPTCP-level ack_seq in multiple times, using possibly different values for the data_ack in the DSS option and to compute the announced rcv…
When was the CVE record for CVE-2026-63867 published?
The CVE record for CVE-2026-63867 was published on July 19, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of August 5, 2026; the record at its source may have been updated since.
Is CVE-2026-63867 actively exploited?
CVE-2026-63867 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (25th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-63867?
CVE-2026-63867 has a CVSS base score of 8.2 (the CNA's own assessment, by linux; NVD's own analysis pending).
How do I remediate CVE-2026-63867?
A fix for CVE-2026-63867 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-63867 are linked in the Vendor Advisories panel on this page.

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