CVE-2026-43383

CRITICALPre-NVD 9.49.4—
EchelonGraph scoreMEDIUM confidence

Score 9.4 from GitHub Security Advisory (severity: CRITICAL) published 2026-05-08. the CNA's CVSS baseline 9.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:linux, epss, ghsa
9.4EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.4Exploit: None knownExposed: 0

A fix is available — apply it.

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

net/tcp-md5: Fix MAC comparison to be constant-time

To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.

CVSS v3
9.4
EG Score
9.4(medium)
EG Risk
47(Track)
EG Risk 47/100SSVC: 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
Severity94% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
37%
KEV
Not listed

Published

May 8, 2026

Last Modified

August 5, 2026

Advisory Details (8)

Auto-updated Sep 14, 2026
No patch confirmed yet.
generic

net/tcp-md5: Fix MAC comparison to be constant-time - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/46d0d6f50dab706637f4c18a470aac20a21900d3
generic

net/tcp-md5: Fix MAC comparison to be constant-time - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/b502e97e29d791ff7a8051f29a414535739be218
generic

net/tcp-md5: Fix MAC comparison to be constant-time - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ae3831b44f477de048287493e184fc3ff913b624
generic

net/tcp-md5: Fix MAC comparison to be constant-time - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/02669e2a4d207068edce7e8b5fafd85822018ce6
generic

net/tcp-md5: Fix MAC comparison to be constant-time - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/5d305a95130a8d08b9545e47f1e18d29d59866cb
generic

net/tcp-md5: Fix MAC comparison to be constant-time - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/345a9530756528d7ca407663d659c3c40e75c3dd
generic

net/tcp-md5: Fix MAC comparison to be constant-time - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ff44ec94d4fc8348600a69de0a8fa1102c23bce8
generic

net/tcp-md5: Fix MAC comparison to be constant-time - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/821c8751fdeecdeecabeb11704dd33439c9e4bbc

Vendor Advisories for CVE-2026-43383(1)

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

Patch Availability(31)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntulinux-virtual-hwe-24.04-edge (6.17.0-40.40) @ questing2026-08-23ubuntu
ubuntulinux-tools-oem-6.17 (6.17.0-1028.28) @ noble2026-08-23ubuntu
ubuntulinux-virtual-6.8 (6.8.0-134.134) @ noble2026-08-23ubuntu
ubuntulinux-virtual-hwe-20.04-edge (5.15.0.185.166) @ jammy2026-08-23ubuntu
ubuntulinux-tools-realtime-hwe-24.04 (6.17.0-1017.19~24.04.1) @ noble2026-08-23ubuntu
ubuntulinux-tools-raspi-6.8 (6.8.0-1060.64) @ noble2026-08-23ubuntu
ubuntulinux-tools-raspi-nolpae (5.15.0.1105.103) @ jammy2026-08-23ubuntu
ubuntulinux-tools-fips-6.8 (6.8.0-134.134+fips1) @ noble2026-08-23ubuntu
ubuntulinux-tools-nvidia-lowlatency-64k-6.8 (6.8.0-1058.61.1) @ noble2026-08-23ubuntu
ubuntulinux-xilinx-zynqmp (6.8.0.1032.33) @ noble2026-08-23ubuntu
ubuntulinux-tools-oracle-edge (5.15.0.1108.114~20.04.1) @ focal2026-08-23ubuntu
ubuntulinux-tools-lowlatency-hwe-20.04-edge (6.8.0-134.134.1) @ noble2026-08-23ubuntu
ubuntulinux-tools-nvidia-tegra-rt-6.8 (6.8.0-1029.30) @ noble2026-08-23ubuntu
ubuntulinux-virtual (3.13.0.214.224) @ trusty2026-08-23ubuntu
ubuntulinux-tools-nvidia-hwe-24.04 (6.17.0-1026.26) @ noble2026-08-23ubuntu
ubuntulinux-tools-raspi-realtime-6.8 (6.8.0-2049.50) @ noble2026-08-23ubuntu
ubuntulinux-xilinx-zynqmp-tools-5.15.0-1074 (5.15.0-1074.78) @ jammy2026-08-23ubuntu
ubuntulinux-virtual-hwe-16.04-edge (4.15.0.253.237) @ bionic2026-08-23ubuntu
ubuntulinux-tools-azure-6.17 (6.17.0-1021.21~24.04.1) @ noble2026-08-23ubuntu
ubuntulinux-tools-fips (4.4.0.1126.128) @ xenial2026-08-23ubuntu
ubuntulinux-tools-azure-fde-6.17 (6.17.0-1018.18~24.04.1) @ noble2026-08-23ubuntu
ubuntulinux-tools-aws-lts-18.04 (4.15.0.1194.192) @ bionic2026-08-23ubuntu
ubuntulinux-virtual-hwe-24.04 (6.17.0-40.40~24.04.1) @ noble2026-08-23ubuntu
ubuntulinux-tools-raspi-6.17 (6.17.0-1021.21) @ questing2026-08-23ubuntu
ubuntulinux-tools-intel-iotg-edge (5.15.0.1106.112~20.04.1) @ focal2026-08-23ubuntu
ubuntulinux-tools-azure-edge (6.8.0-1063.71~22.04.1) @ jammy2026-08-23ubuntu
ubuntulinux-tools-azure-fde-lts-24.04 (6.8.0-1062.69) @ noble2026-08-23ubuntu
ubuntulinux-tools-azure-fde-6.8 (6.8.0-1062.69~22.04.1) @ jammy2026-08-23ubuntu
ubuntulinux-tools-azure-fips-5.15 (5.15.0.1116.101) @ jammy2026-08-23ubuntu
ubuntulinux-virtual-hwe-18.04-edge (5.4.0.233.253~18.04.1) @ bionic2026-08-23ubuntu
linuxKernel @ 5.10.253—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.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
linux5.10.103-1 ... 5.10.92-2 (53 versions)5.10.257-1—
Debian:12(1)
PackageVulnerable rangeFixed inDependents
linux6.1.106-1 ... 6.1.99-1 (48 versions)6.1.170-1—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
linux6.12.38-1 ... 6.12.85-1~bpo12+1 (17 versions)6.12.85-1—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
linux6.12.100-1 ... 6.19~rc8-1~exp1 (122 versions)6.19.10-1—

All Vendor Advisories

(25)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 7× in last 7d / 32× 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.

Showing the most recent 100 of 349 total refreshes for this CVE.

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

Related CVEs(same product + same vendor)

Frequently asked(5)

What is CVE-2026-43383?
CVE-2026-43383 is a critical vulnerability published on May 8, 2026. In the Linux kernel, the following vulnerability has been resolved: net/tcp-md5: Fix MAC comparison to be constant-time To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.
When was CVE-2026-43383 disclosed?
CVE-2026-43383 was first published in the National Vulnerability Database on May 8, 2026, with the most recent update on August 5, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-43383 actively exploited?
CVE-2026-43383 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 62.5% of all scored CVEs.
What is the CVSS score of CVE-2026-43383?
CVE-2026-43383 has a CVSS v4.0 base score of 9.4 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-43383?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-43383, 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.

Dependency Blast Radius

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