Two-factor authentication (2FA) is a critical security layer designed to protect your accounts even if your password falls into the wrong hands. It adds an extra step to verify your identity, often through a code sent to your phone or generated by an app. Unfortunately, a recent discovery in Nextcloud Server revealed a way to bypass this crucial protection.<\/p>\n
This vulnerability, identified as CVE-2026-45690, allowed attackers who already knew a user’s password to cleverly sidestep their 2FA. When a user started the login process, Nextcloud would create a temporary session token before asking for the second factor. An attacker could grab this temporary token and reuse it to gain unauthorized access, effectively bypassing the 2FA safeguard.<\/p>\n
Product Name:<\/strong> Nextcloud Server This authentication bypass vulnerability impacts specific versions of Nextcloud Server and Nextcloud Enterprise Server:<\/p>\n The vulnerability has been thoroughly analyzed, and Nextcloud has released patches to address the issue. Users are strongly advised to update their installations promptly to protect against potential exploitation.<\/p>\n Rated as Medium<\/strong> severity with a CVSS score of 5.9, this vulnerability presents a notable risk. The attack vector is via the network, meaning an attacker doesn’t need physical access to your server. While the attack complexity is considered high (requiring some specific knowledge or conditions), the fact that no user interaction is needed once the password is known makes it a serious concern. The vulnerability could lead to a high impact on data integrity, allowing unauthorized modification, and a low impact on confidentiality, potentially exposing sensitive information.<\/p>\n Nextcloud has released security updates to fix this authentication bypass. The most effective solution is to upgrade your Nextcloud installation to a patched version immediately.<\/p>\n At the time of this writing, there are no known workarounds for this vulnerability. Updating to the patched versions is the only recommended mitigation.<\/p>\n https:\/\/github.com\/nextcloud\/security-advisories\/security\/advisories\/GHSA-jgcj-v42r-9922 Two-factor authentication (2FA) is a critical security layer designed to protect your accounts even if your password falls into the wrong hands. It adds an extra step to verify your identity, often through a code sent to your phone or generated by an app. Unfortunately, a recent discovery in Nextcloud Server revealed a way to […]<\/p>\n","protected":false},"author":17,"featured_media":2652,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[1138,907,770,1123,765],"class_list":["post-3680","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-security","tag-2fa-bypass","tag-authentication","tag-nextcloud","tag-nextcloud-server","tag-security-update"],"blocksy_meta":[],"yoast_head":"\n
\nCVE ID:<\/strong> CVE-2026-45690
\nPublished:<\/strong> June 1, 2026
\nSeverity:<\/strong> Medium (CVSS: 5.9)
\nStatus:<\/strong> Analyzed<\/p>\nAffected Products<\/h2>\n
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Current Status<\/h2>\n
Severity Level<\/h2>\n
Possible Solutions<\/h2>\n
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References<\/h2>\n
\nhttps:\/\/github.com\/nextcloud\/server\/pull\/59758
\nhttps:\/\/hackerone.com\/reports\/3639301<\/p>\n","protected":false},"excerpt":{"rendered":"