Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-4408

43
FAUCET Score

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.

First published: May 28, 2026Last modified: Jul 2, 2026

Impacted Technologies

VendorProductVersion(s)CPE
4.0CPE matchmatch criteria
cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
>= 4.1.0, < 4.21.0CPE matchmatch criteria
cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*
6.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
7.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.0CRITICAL

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.2
Impact Score
6.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.50%
Probability of exploitation in next 30 days
EPSS Percentile
83.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0250 is in the 73rd percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

ubuntupatch availablevia ubuntu_usn
Product: samba (jammy)Fixed in: 2:4.15.13+dfsg-0ubuntu1.12
ubuntupatch availablevia ubuntu_usn
Product: samba (noble)Fixed in: 2:4.19.5+dfsg-4ubuntu9.6
ubuntupatch availablevia ubuntu_usn
Product: samba (questing)Fixed in: 2:4.22.3+dfsg-4ubuntu2.4
ubuntupatch availablevia ubuntu_usn
Product: samba (resolute)Fixed in: 2:4.23.6+dfsg-1ubuntu2.1

Vendor Advisories (1)

ubuntuUSN-8306-1

Samba vulnerabilities

May 26, 2026

References

security.access.redhat.com / data/csaf/v2/vex/2026/cve-2026-4408.json
access.redhat.com / errata/RHSA-2026:22644
Issue Tracking
access.redhat.com / errata/RHSA-2026:22963
Issue Tracking
access.redhat.com / errata/RHSA-2026:25049
access.redhat.com / errata/RHSA-2026:25979
access.redhat.com / errata/RHSA-2026:28053
access.redhat.com / errata/RHSA-2026:28054
access.redhat.com / errata/RHSA-2026:28055
access.redhat.com / errata/RHSA-2026:28056
access.redhat.com / errata/RHSA-2026:28057
access.redhat.com / errata/RHSA-2026:28058
access.redhat.com / errata/RHSA-2026:28132
access.redhat.com / errata/RHSA-2026:29799
access.redhat.com / errata/RHSA-2026:29833
access.redhat.com / errata/RHSA-2026:29863
access.redhat.com / security/cve/CVE-2026-4408
Third Party Advisory
bugzilla.redhat.com / show_bug.cgi
Issue TrackingThird Party Advisory
bugzilla.samba.org / show_bug.cgi
Issue TrackingVendor Advisory