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Fencer Vulns
high 8.8

CVE-2021-3738 json

In DCE/RPC it is possible to share the handles (cookies for resource state) between multiple connections via a mechanism called 'associatio…

published 2022-03-02 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-27014

cvss
8.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.0%
EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits
0
none known

Summary

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.

Patch / fix

  • samba samba 4.13.14, 4.14.10, 4.15.2
  • samba Debian 14, Debian 13, Debian 12 2:4.13.14+dfsg-1

debian advisories DEBIAN-CVE-2021-3738

  • samba Ubuntu 20.04 LTS 2:4.13.14+dfsg-0ubuntu0.20.04.1
  • samba Ubuntu 22.04 LTS 2:4.13.14+dfsg-0ubuntu1

ubuntu advisories UBUNTU-CVE-2021-3738

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • samba Enterprise Storage 7 4.13.13+git.545.5897c2d94f3-3.12.1
  • ldb Enterprise Storage 7 2.2.2-4.6.1
  • ldb SLE Module for Basesystem 15 SP3, SLE Micro 5.1 2.2.2-3.3.1
  • samba SLE Module for Python 2 15 SP3, SLE Module for Basesystem 15 SP3, SLE High Availability Extension 15 SP3 4.13.13+git.528.140935f8d6a-3.12.1

suse advisories SUSE-SU-2022:0361-1SUSE-SU-2021:3647-1

  • samba openSUSE Tumbleweed 4.15.2+git.193.a4d6307f1fd-1.1
  • ldb openSUSE Leap 15.3 2.2.2-3.3.1
  • samba openSUSE Leap 15.3 4.13.13+git.528.140935f8d6a-3.12.1

opensuse advisories openSUSE-SU-2024:11631-1openSUSE-SU-2021:3647-1

  • samba Alpine 3.13 4.13.17-r0
  • samba Alpine 3.14 4.14.12-r0
  • samba Alpine 3.24, Alpine 3.23, Alpine 3.22 +7 more 4.15.2-r0

alpine advisories ALPINE-CVE-2021-3738

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • samba Azure Linux 3.0 4.18.3-1

azure linux advisories AZL-37005

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

  • samba Arch Linux 4.15.2-1

arch linux advisories AVG-2538

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-3738 updated cvss 7.6

samba: Use after free in Samba AD DC RPC server

  • Red Hat Enterprise Linux 6 samba, samba4, samba4-dc, samba-swat, samba4-libs, samba4-pidl, +17 more Red Hat Enterprise Linux 7 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +18 more Red Hat Enterprise Linux 8 ctdb, samba, libnetapi, ctdb-tests, samba-libs, samba-pidl, +24 more Red Hat Enterprise Linux 9 ctdb, samba, libldb, ldb-tools, libnetapi, samba-libs, +27 more Red Hat Storage 3 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +21 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.05% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P

Affected products

  • n/a samba

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.