CVE-2026-4408

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 2.5%, top 17% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 3%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

A flaw was found in Samba. A remote attacker can exploit a misconfiguration in Samba file servers and classic domain controllers that use the "check password script" feature. If this script is configured with the %u substitution character, the client-controlled username is passed without proper escaping of shell meta-characters. This vulnerability allows an attacker to achieve remote command execution on the affected system. This issue primarily affects non-standard configurations where the "check password script" is used with %u and the samba-dcerpcd service is started as a system service.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
45(Track)
EG Risk 45/100SSVC: 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
Severity98% × 45%
Exploitation3% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
83.0%
KEV
Not listed

Published

May 28, 2026

Last Modified

July 15, 2026

Advisory Details (13)

Auto-updated Jul 16, 2026
Patch available. Sources: redhat.
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.4 Extended Update Support

https://access.redhat.com/errata/RHSA-2026:28058
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.6 Extended Update Support

https://access.redhat.com/errata/RHSA-2026:28057
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Serv

https://access.redhat.com/errata/RHSA-2026:28056
redhat Patch Available

Affected: Red Hat Enterprise Linux 10.0 Extended Update Support.

https://access.redhat.com/errata/RHSA-2026:28055
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions.

https://access.redhat.com/errata/RHSA-2026:28054
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions.

https://access.redhat.com/errata/RHSA-2026:28053
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.6 Extended Update Support.

https://access.redhat.com/errata/RHSA-2026:25979
redhat Patch Available

Affected: Red Hat Enterprise Linux 9.

https://access.redhat.com/errata/RHSA-2026:25049
redhat Patch Available

Affected: Red Hat Enterprise Linux 10.

https://access.redhat.com/errata/RHSA-2026:22963
redhat Patch Available

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2026:22644
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-4408
generic

16034 – (CVE-2026-4408) CVE-2026-4408 [SECURITY] Remote Code Execution in SAMR

https://bugzilla.samba.org/show_bug.cgi?id=16034
redhat Patch Available

2479762 – (CVE-2026-4408) CVE-2026-4408 samba: Remote Code Execution in SAMR

Affected: Red Hat Enterprise Linux 8

https://bugzilla.redhat.com/show_bug.cgi?id=2479762

Vendor Advisories for CVE-2026-4408(15)

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

Patch Availability(15)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuwinbind (2:4.23.6+dfsg-1ubuntu2.1) @ resolute2026-07-12ubuntu
redhatrhcos-4.19.9.6.202606241344-02026-07-02redhat
redhatrhcos-4.20.9.6.202606241928-02026-06-30redhat
redhatrhcos-4.21.9.6.202606241859-02026-06-30redhat
redhatsamba-0:4.13.3-12.el8_4.12026-06-23redhat
redhatsamba-0:4.17.5-7.el8_8.12026-06-23redhat
redhatsamba-0:4.15.5-16.el8_6.12026-06-23redhat
redhatsamba-0:4.10.16-26.el7_9.12026-06-23redhat
redhatsamba-0:4.17.5-105.el9_2.52026-06-23redhat
redhatsamba-0:4.19.4-105.el9_4.42026-06-23redhat
redhatsamba-0:4.21.3-114.el10_0.12026-06-23redhat
redhatsamba-0:4.21.3-14.el9_6.12026-06-15redhat
redhatsamba-0:4.23.5-10.el9_82026-06-10redhat
redhatsamba-0:4.19.4-16.el8_102026-06-03redhat
redhatsamba-0:4.23.5-109.el10_22026-06-03redhat

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.

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 9× in last 7d / 106× 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 357 total refreshes for this CVE.

  1. 2026-07-23 03:14 UTCEG score recompute▲ 0.80
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:25 UTCEPSS rescore
  4. 2026-07-20 17:08 UTCEPSS rescore
  5. 2026-07-19 14:31 UTCEPSS rescore
  6. 2026-07-19 14:31 UTCEPSS rescore
  7. 2026-07-19 02:29 UTCEPSS rescore
  8. 2026-07-18 10:04 UTCEPSS rescore
  9. 2026-07-16 17:03 UTCEPSS rescore
  10. 2026-07-15 16:57 UTCEPSS rescore
  11. 2026-07-15 16:57 UTCEPSS rescore
  12. 2026-07-15 02:26 UTCNVD updateCVSS v3 → 9.8
  13. 2026-07-15 02:00 UTCEPSS rescore
  14. 2026-07-15 02:00 UTCEPSS rescore
  15. 2026-07-15 01:21 UTCMITRE cvelistV5CVSS v3 → 9
  16. 2026-07-13 22:31 UTCEPSS rescore
  17. 2026-07-13 06:13 UTCEPSS rescore
  18. 2026-07-12 05:46 UTCEPSS rescore
  19. 2026-07-12 01:37 UTCVendor advisory
  20. 2026-07-12 01:37 UTCGHSA enrichment
  21. 2026-07-11 21:36 UTCVendor advisory
  22. 2026-07-11 21:36 UTCGHSA enrichment
  23. 2026-07-11 08:27 UTCEPSS rescore
  24. 2026-07-09 19:10 UTCEPSS rescore
  25. 2026-07-08 22:48 UTCVendor advisory
Show 75 more
  1. 2026-07-08 22:48 UTCGHSA enrichment
  2. 2026-07-08 18:41 UTCVendor advisory
  3. 2026-07-08 18:41 UTCGHSA enrichment
  4. 2026-07-08 15:16 UTCEPSS rescore
  5. 2026-07-07 13:46 UTCEPSS rescore
  6. 2026-07-06 16:27 UTCEPSS rescore
  7. 2026-07-05 02:30 UTCEPSS rescore
  8. 2026-07-04 06:31 UTCEPSS rescore
  9. 2026-07-02 23:29 UTCVendor advisory
  10. 2026-07-02 23:28 UTCGHSA enrichment
  11. 2026-07-02 14:31 UTCVendor advisory
  12. 2026-07-02 14:31 UTCGHSA enrichment
  13. 2026-07-01 20:32 UTCVendor advisory
  14. 2026-07-01 20:31 UTCGHSA enrichment
  15. 2026-07-01 15:07 UTCEPSS rescore
  16. 2026-07-01 14:00 UTCVendor advisory
  17. 2026-07-01 14:00 UTCGHSA enrichment
  18. 2026-07-01 09:14 UTCVendor advisory
  19. 2026-07-01 09:14 UTCGHSA enrichment
  20. 2026-07-01 03:24 UTCVendor advisory
  21. 2026-07-01 03:24 UTCGHSA enrichment
  22. 2026-06-30 23:22 UTCEPSS rescore
  23. 2026-06-30 06:13 UTCVendor advisory
  24. 2026-06-30 06:13 UTCGHSA enrichment
  25. 2026-06-30 02:14 UTCVendor advisory
  26. 2026-06-30 02:14 UTCGHSA enrichment
  27. 2026-06-29 19:45 UTCVendor advisory
  28. 2026-06-29 19:45 UTCGHSA enrichment
  29. 2026-06-29 14:06 UTCEPSS rescore
  30. 2026-06-29 14:06 UTCEPSS rescore
  31. 2026-06-29 13:47 UTCVendor advisory
  32. 2026-06-29 13:47 UTCGHSA enrichment
  33. 2026-06-29 00:30 UTCVendor advisory
  34. 2026-06-29 00:30 UTCGHSA enrichment
  35. 2026-06-28 20:31 UTCVendor advisory
  36. 2026-06-28 20:31 UTCGHSA enrichment
  37. 2026-06-28 16:33 UTCVendor advisory
  38. 2026-06-28 16:32 UTCGHSA enrichment
  39. 2026-06-28 14:07 UTCEPSS rescore
  40. 2026-06-28 10:44 UTCVendor advisory
  41. 2026-06-28 10:44 UTCGHSA enrichment
  42. 2026-06-28 06:39 UTCVendor advisory
  43. 2026-06-28 06:38 UTCGHSA enrichment
  44. 2026-06-28 04:56 UTCEPSS rescore
  45. 2026-06-28 04:56 UTCEPSS rescore
  46. 2026-06-28 02:16 UTCVendor advisory
  47. 2026-06-28 02:16 UTCGHSA enrichment
  48. 2026-06-27 22:19 UTCVendor advisory
  49. 2026-06-27 22:19 UTCGHSA enrichment
  50. 2026-06-27 18:21 UTCVendor advisory
  51. 2026-06-27 18:21 UTCGHSA enrichment
  52. 2026-06-27 13:43 UTCVendor advisory
  53. 2026-06-27 13:43 UTCGHSA enrichment
  54. 2026-06-27 09:37 UTCVendor advisory
  55. 2026-06-27 09:37 UTCGHSA enrichment
  56. 2026-06-27 05:39 UTCVendor advisory
  57. 2026-06-27 05:39 UTCGHSA enrichment
  58. 2026-06-27 03:08 UTCEPSS rescore
  59. 2026-06-27 01:40 UTCVendor advisory
  60. 2026-06-27 01:40 UTCGHSA enrichment
  61. 2026-06-26 20:52 UTCVendor advisory
  62. 2026-06-26 20:52 UTCGHSA enrichment
  63. 2026-06-26 16:55 UTCVendor advisory
  64. 2026-06-26 16:55 UTCGHSA enrichment
  65. 2026-06-26 02:06 UTCVendor advisory
  66. 2026-06-26 02:06 UTCGHSA enrichment
  67. 2026-06-25 20:44 UTCVendor advisory
  68. 2026-06-25 20:44 UTCGHSA enrichment
  69. 2026-06-25 16:44 UTCVendor advisory
  70. 2026-06-25 16:44 UTCGHSA enrichment
  71. 2026-06-25 13:49 UTCEPSS rescore
  72. 2026-06-25 12:38 UTCVendor advisory
  73. 2026-06-25 12:38 UTCGHSA enrichment
  74. 2026-06-25 08:40 UTCVendor advisory
  75. 2026-06-25 08:39 UTCGHSA enrichment

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-4408?
CVE-2026-4408 is a critical vulnerability published on May 28, 2026. A flaw was found in Samba. A remote attacker can exploit a misconfiguration in Samba file servers and classic domain controllers that use the "check password script" feature. If this script is configured with the %u substitution character, the client-controlled username is passed without proper…
When was CVE-2026-4408 disclosed?
CVE-2026-4408 was first published in the National Vulnerability Database on May 28, 2026, with the most recent update on July 15, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-4408 actively exploited?
CVE-2026-4408 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 83.0% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-4408?
CVE-2026-4408 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-4408?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-4408, 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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