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Fencer Vulns
high 7.5

CVE-2021-23192 json

A flaw was found in the way samba implemented DCE/RPC.

published 2022-03-02 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-10299

cvss
7.5
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 80%
public exploits
0
none known

Summary

A flaw was found in the way samba implemented DCE/RPC. If a client to a Samba server sent a very large DCE/RPC request, and chose to fragment it, an attacker could replace later fragments with their own data, bypassing the signature requirements.

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-2021-23192

  • 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-2021-23192

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 RHEL 8 4.14.5-7.el8_5
  • ctdb RHEL 8 4.14.5-7.el8_5
  • samba-libs RHEL 8 4.14.5-7.el8_5
  • samba-pidl RHEL 8 4.14.5-7.el8_5
  • samba-test RHEL 8 4.14.5-7.el8_5
  • libwbclient RHEL 8 4.14.5-7.el8_5
  • libsmbclient RHEL 8 4.14.5-7.el8_5
  • samba-client RHEL 8 4.14.5-7.el8_5

red hat advisories RHSA-2022:0008RHSA-2021:5082RHSA-2021:4843

  • samba Enterprise Storage 7 4.13.13+git.545.5897c2d94f3-3.12.1
  • ldb Enterprise Storage 7 2.2.2-4.6.1
  • samba SLE Module for Python 2 15 SP2, SLE Module for Basesystem 15 SP2, SLE High Availability Extension 15 SP2 4.11.14+git.308.666c63d4eea-4.28.1
  • samba SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 +1 more 4.10.18+git.339.c912385a5e1-3.41.1
  • 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-2021:3650-1SUSE-SU-2021:3649-1SUSE-SU-2021:3647-1

  • samba openSUSE Tumbleweed 4.15.2+git.193.a4d6307f1fd-1.1
  • samba openSUSE Leap 15.2 4.11.14+git.308.666c63d4eea-lp152.3.28.1
  • samba openSUSE Leap 15.3 4.11.14+git.308.666c63d4eea-4.28.1
  • 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-2021:1471-1openSUSE-SU-2021:3650-1openSUSE-SU-2021:3647-1

  • samba-vfs-iouring AlmaLinux 8 4.14.5-7.el8_5

almalinux advisories ALSA-2021:5082

  • samba Rocky Linux 8 4.14.5-7.el8_5

rocky linux advisories RLSA-2021:5082

  • 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-2021-23192

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-37002

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-2021-23192 updated cvss 4.8

samba: Subsequent DCE/RPC fragment injection vulnerability

  • Red Hat CodeReady Linux Builder (v. 8) samba-devel 4.14.5-7.el8_5, ctdb-debuginfo 4.14.5-7.el8_5, samba-debuginfo 4.14.5-7.el8_5, libwbclient-devel 4.14.5-7.el8_5, samba-debugsource 4.14.5-7.el8_5, libsmbclient-devel 4.14.5-7.el8_5, +17 more Red Hat Enterprise Linux AppStream (v. 8) samba-vfs-iouring 4.14.5-7.el8_5 Red Hat Enterprise Linux BaseOS (v. 8) ctdb 4.14.5-7.el8_5, samba 4.14.5-7.el8_5, samba-libs 4.14.5-7.el8_5, samba-pidl 4.14.5-7.el8_5, samba-test 4.14.5-7.el8_5, libwbclient 4.14.5-7.el8_5, +15 more
    fixed: vendor fix “Setting ~~~ dcesrv:max auth states=0 ~~~ in the smb.conf will provide some mitigation against this issue.” RHSA-2021:5082
  • Red Hat Enterprise Linux BaseOS EUS (v.8.4) ctdb 4.13.3-8.el8_4, samba 4.13.3-8.el8_4, ctdb-tests 4.13.3-8.el8_4, samba-libs 4.13.3-8.el8_4, samba-pidl 4.13.3-8.el8_4, samba-test 4.13.3-8.el8_4, +16 more Red Hat Enterprise Linux CRB EUS (v.8.4) samba-devel 4.13.3-8.el8_4, ctdb-debuginfo 4.13.3-8.el8_4, samba-debuginfo 4.13.3-8.el8_4, libwbclient-devel 4.13.3-8.el8_4, samba-debugsource 4.13.3-8.el8_4, libsmbclient-devel 4.13.3-8.el8_4, +18 more
    fixed: vendor fix “Setting ~~~ dcesrv:max auth states=0 ~~~ in the smb.conf will provide some mitigation against this issue.” RHSA-2022:0008
  • Red Hat Gluster 3.5 Samba on RHEL-8 ctdb 4.14.5-204.el8rhgs, samba 4.14.5-204.el8rhgs, samba-libs 4.14.5-204.el8rhgs, samba-pidl 4.14.5-204.el8rhgs, libwbclient 4.14.5-204.el8rhgs, libsmbclient 4.14.5-204.el8rhgs, +12 more
    fixed: vendor fix “Setting ~~~ dcesrv:max auth states=0 ~~~ in the smb.conf will provide some mitigation against this issue.” RHSA-2021:4843
  • Red Hat Enterprise Linux 6 samba, samba-swat, libsmbclient, samba-client, samba-common, samba-winbind, +4 more Red Hat Enterprise Linux 7 ctdb, samba, samba-dc, ctdb-tests, samba-libs, samba-pidl, +18 more Red Hat Enterprise Linux 9 ctdb, samba, libldb, ldb-tools, libnetapi, samba-libs, +27 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

1.95% chance of exploitation in the next 30 days, higher than 80% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:P/A:N

Affected products

  • n/a samba

Classification

Weakness
  • CWE-20 Improper Input Validation

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.