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A newly disclosed vulnerability in Webmin’s HTTP server component, miniserv.pl, allows an unauthenticated remote attacker to impersonate any user configured with an SSL client certificate by sending a forged HTTP header and spoofing certificate distinguished names (DNs). The issue is tracked as CVE-2026-56020, classified as CWE-290: Authentication Bypass by Spoofing, and is rated 8.1 HIGH under CVSS v3.1 and 9.2 CRITICAL under CVSS v4.0.
The flaw affects Webmin versions before 2.641, and version 2.641 contains the fix. Public advisories recommend upgrading to 2.641 or later and verifying that SSL client certificate validation is correctly configured. The CVE record credits Adem El Adeb of vulone.com/vul1.com for reporting the issue.
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2 events from the most recent confirmed update back to the earliest known activity.
On 2026-06-18, CVE-2026-56020 was published describing a spoofing-based authentication bypass in Webmin's miniserv.pl HTTP server component. The flaw was rated 8.1 under CVSS v3.1 and 9.2 under CVSS v4.0, with credit given to Adem El Adeb.
Webmin version 2.641 was identified as containing the fix for an authentication bypass flaw in miniserv.pl that could let an unauthenticated attacker impersonate users with configured SSL client certificates. Versions before 2.641 are affected.
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A critical authentication bypass flaw, tracked as **`CVE-2026-41940`**, affects **cPanel & WHM** and **WP Squared** deployments and has been publicly reported as under active exploitation. The vulnerability can let unauthenticated remote attackers bypass normal login controls in certain conditions and potentially obtain administrative access to internet-facing hosting systems that manage websites, databases, email, DNS, SSL certificates, and customer accounts. Guidance tied to the disclosure urges organizations to apply vendor-patched builds immediately and investigate for signs of compromise, as a successful breach could expose downstream environments and sensitive business data. Recommended response actions include isolating affected servers, rotating credentials, removing attacker persistence, and rebuilding compromised systems, alongside longer-term hardening such as **MFA**, network segmentation, reduced internet exposure, tighter privileged access, and continuous vulnerability monitoring.
Jun 29, 2026
WebPros cPanel disclosed and patched a critical authentication bypass flaw in **cPanel & WHM** and **WP Squared**, now tracked as `CVE-2026-41940` with a **CVSS 9.8** score. The bug affects all supported cPanel & WHM versions after `11.40` prior to fixed releases, and reporting indicates some unsupported versions are likely vulnerable as well. Researchers said the issue stems from improper session handling tied to a **CRLF injection** in the login flow, allowing unauthenticated remote attackers to poison session data and gain administrator or root-level access to exposed hosting control panels. cPanel released emergency updates across supported branches, published detection guidance, and advised administrators to force updates, restart `cpsrvd`, and investigate session files and logs for signs of compromise. Multiple sources reported the flaw was **actively exploited in the wild** before patches were issued, with hosting providers such as **Namecheap** and **KnownHost** taking emergency action by restricting access to management ports like `2083` and `2087` while deploying fixes. **CISA** added `CVE-2026-41940` to its **Known Exploited Vulnerabilities** catalog and ordered federal agencies to remediate quickly, while national cyber agencies in Canada, Austria, and Belgium also warned of the risk. Public technical analysis, proof-of-concept code, and exploit tooling released after disclosure increased the likelihood of broad opportunistic attacks against internet-exposed cPanel systems, which researchers estimated number in the hundreds of thousands to more than a million, raising the risk of website compromise, credential theft, ransomware, phishing, and multi-tenant hosting breaches.
Sep 3, 2026
cPanel disclosed and patched a critical authentication bypass in cPanel & WHM, tracked as **`CVE-2026-41940`**, after reports of active in-the-wild exploitation against hosting infrastructure. The flaw affects authentication paths in supported versions and can let unauthenticated attackers reach administrative interfaces, forge authenticated sessions, and potentially gain control of hosted websites, databases, email accounts, and server configuration. Government and industry alerts warned that shared hosting environments face outsized risk because a single compromised server can expose many downstream customer sites, and some providers temporarily restricted cPanel and WHM login ports while applying fixes. Public technical analysis and a GitHub proof-of-concept described an exploit chain involving manipulated HTTP headers and session cookie handling to create forged privileged sessions, including possible root-level WHM access. Separately, cPanel also patched three additional vulnerabilities in cPanel & WHM and **WP Squared**—**`CVE-2026-29201`**, **`CVE-2026-29202`**, and **`CVE-2026-29203`**—that enable arbitrary file read through path traversal, Perl code injection leading to remote code execution, and denial-of-service via unsafe symlink handling. The most severe of the newly disclosed flaws, **`CVE-2026-29202`**, affects the `create_user` API and can allow arbitrary Perl code execution on the server, reinforcing calls for immediate upgrades, restricted access to management interfaces, and log review for suspicious authorization and cookie activity.
Jun 29, 2026