Skip to main content
Meet us at Black Hat USA 2026— Las Vegas, August 1–6Book a Meeting
Mallory
Medium

Samba certificate auto-enrollment GPO CA certificate installation over HTTP without verification

IdentifiersCVE-2026-3012CWE-494

CVE-2026-3012 is a flaw in Samba's certificate auto-enrollment Group Policy handling affecting Samba versions since 4.16. When certificate auto-enrollment is enabled on a domain member, Samba may fetch a CA certificate over plain HTTP and install it into the local trust store without proper verification. The vulnerable behavior occurs in the auto-enrollment GPO path used by domain members, where Samba follows a certificate retrieval URL pattern associated with Microsoft NDES even though a more secure encrypted LDAP channel is available for domain members. Because the CA certificate is obtained over an unencrypted and insufficiently validated channel, an attacker who can intercept or redirect the HTTP traffic can substitute an attacker-controlled CA certificate, which is then trusted by the affected host.

Share:
For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an attacker to cause installation of a malicious certificate authority certificate into the affected system's trust store. This can undermine the host's trust model and enable interception, spoofing, or impersonation of otherwise trusted communications, with high confidentiality and integrity impact. The published CVSS v3.1 vector is AV:A/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N with a base score of 8.0. No direct availability impact is described.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, disable the vulnerable certificate auto-enrollment GPO path so the affected code does not run. In particular, avoid enabling certificate auto-enrollment on domain members, and ensure Group Policy processing is not enabled where unnecessary. If smb.conf does not contain 'apply group policies = yes', the vulnerable code path does not execute. Also reduce exposure to local network interception or traffic redirection and avoid allowing CA certificate retrieval over unencrypted HTTP.

Remediation

Patch, then assume compromise.

Upgrade Samba to a fixed release. The issue is addressed in Samba 4.22.10, 4.23.8, and 4.24.3. The Samba fix removes the HTTP certificate download behavior and relies on LDAP values instead. Administrators should apply the vendor patch or upgrade promptly to a release containing the fix.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
Red HatEnterprise Linuxoperating_system
Red HatOpenshift Container Platformapplication
SambaSambaapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity8

Community discussion across Reddit, Mastodon, and other social sources.