CVE-2026-56020
Webmin HTTP header authentication bypass
Description
The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.641.
INFO
Published Date :
June 18, 2026, 5:16 p.m.
Last Modified :
June 22, 2026, 5:52 p.m.
Remotely Exploit :
Yes !
Source :
9119a7d8-5eab-497f-8521-727c672e3725
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 9119a7d8-5eab-497f-8521-727c672e3725 | |||||
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 9119a7d8-5eab-497f-8521-727c672e3725 | ||||
| CVSS 4.0 | CRITICAL | 9119a7d8-5eab-497f-8521-727c672e3725 |
Solution
- Update Webmin to version 2.641 or later.
- Ensure SSL client certificate validation is correctly configured.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-56020.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-56020 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-56020
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-56020 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-56020 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 22, 2026
Action Type Old Value New Value Changed SSVC {'id': 'CVE-2026-56020', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-18T00:00:00+00:00'} {'id': 'CVE-2026-56020', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-19T03:55:50.732526Z'} -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 19, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-56020', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-06-18T00:00:00+00:00'} -
New CVE Received by 9119a7d8-5eab-497f-8521-727c672e3725
Jun. 18, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'Webmin', 'product': 'Webmin', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '2.641', 'versionType': 'custom'}, {'status': 'unaffected', 'version': '2.641'}], 'defaultStatus': 'unknown'}] Added SSVC {'id': 'CVE-2026-56020', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'total'}], 'version': '2.0.3', 'timestamp': '2026-05-29T20:04:47.266910Z'} Added Description The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.641. Added CVSS V4.0 AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Added CWE CWE-290 Added Reference https://github.com/webmin/webmin/releases/tag/2.641 Added Reference https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-169-02.json Added Reference https://webmin.com/security/#webmin-prior-to-2641 Added Reference https://www.cve.org/CVERecord?id=CVE-2026-56020