CVE-2020-25721Network attack vector

Privilege impersonation via mutable Kerberos client names

Published Mar 16, 2022 · Updated Aug 4, 2024

Authorization weakness in Samba allows remote authenticated users to impersonate privileged account names through crafted Kerberos requests. The AD DC omits an easily parsed stable SID from UPN_DNS_INFO, leaving non-Samba acceptors to authorize the mutable Kerberos client name. Exploitation requires delegated user or computer creation rights, including the default machine-account quota, and impact depends on the accepting application.

CVSS severity8.8
High
EPSS probability2.06%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authorization weakness in Samba allows remote authenticated users to impersonate privileged account names through crafted Kerberos requests. The AD DC omits an easily parsed stable SID from UPN_DNS_INFO, leaving non-Samba acceptors to authorize the mutable Kerberos client name. Exploitation requires delegated user or computer creation rights, including the default machine-account quota, and impact depends on the accepting application.

The record

CVE
CVE-2020-25721
Published
Mar 16, 2022
Updated
Aug 4, 2024
Vendor
PPP Project
Product
Samba
Classifications
CWE-20, T1136.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 16, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=Affected - All versions since Samba 4.0.0, Fixed-In - v4.15.2, v4.14.10 and v4.13.14

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

PPP Project · Sambaversion=Affected - All versions since Samba 4.0.0, Fixed-In - v4.15.2, v4.14.10 and v4.13.14

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-20Improper Input Validation
T1136.002Domain Account

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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