What’s Vulnerable › Vulnerabilities

CVE-2021-3738

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-03-02 · updated 2026-06-17
• Weakness: CWE-416

Description

In DCE/RPC it is possible to share the handles (cookies for resource state) between multiple connections via a mechanism called 'association groups'. These handles can reference connections to our sam.ldb database. However while the database was correctly shared, the user credentials state was only pointed at, and when one connection within that association group ended, the database would be left pointing at an invalid 'struct session_info'. The most likely outcome here is a crash, but it is possible that the use-after-free could instead allow different user state to be pointed at and this might allow more privileged access.

Affected products

• Samba: from 4.0.0 before 4.13.14; from 4.14.0 before 4.14.10; from 4.15.0 before 4.15.2 — fixed in 4.13.14, 4.14.10, 4.15.2

How to fix

Upgrade to a fixed version: Samba 4.13.14, 4.14.10, 4.15.2. Check the vendor advisory for mitigations.

References

• https://bugzilla.redhat.com/show_bug.cgi?id=2021726
• https://bugzilla.samba.org/show_bug.cgi?id=14468
• https://security.gentoo.org/glsa/202309-06
• https://www.samba.org/samba/security/CVE-2021-3738.html
• https://bugzilla.redhat.com/show_bug.cgi?id=2021726
• https://bugzilla.samba.org/show_bug.cgi?id=14468
• https://security.gentoo.org/glsa/202309-06
• https://www.samba.org/samba/security/CVE-2021-3738.html

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