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CVE-2026-48902 is a vulnerability in the Joomla! CMS that causes the password and username reset features to generate plain `http` links even when the site is accessed over an `https` connection – if the “Force SSL” flag is not explicitly enabled in the server configuration. At its core, the issue is a failure to enforce transport-layer encryption during one of the most sensitive user interactions: account recovery.
The vulnerability lives in the link generation logic of the authentication system. When a user requests a password or username reset, the application should always produce a secure `https` URL, regardless of the current connection state or global settings. However, the flawed implementation checks the presence of the `Force SSL` flag. If that flag is missing or set to false, the reset link is constructed using the `http` protocol – even if the user is already browsing the site over an `https` connection. This inconsistency creates a mixed-protocol scenario where the reset token is transmitted in plaintext, completely bypassing the security guarantees of HTTPS.
An attacker can exploit this weakness by passively listening on a network segment between the user and the server (e.g., on public Wi-Fi, compromised routers, or enterprise networks with insufficient segmentation). Because the reset link is sent as an `http` link, it is not encrypted, and the attacker can intercept it in real time. Once the attacker obtains the plaintext reset URL, they can visit it directly, set a new password of their choice, and fully compromise the victim’s account. From there, the attacker can access private data, perform lateral movement within the site, and potentially escalate privileges if the compromised account belongs to an administrator.
This vulnerability is particularly dangerous because it does not require any user interaction beyond requesting a password reset – a common and everyday action. It also bypasses all the protections that HTTPS is meant to provide, such as confidentiality, integrity, and authentication of the connection. The CWE mappings are CWE-312 (Cleartext Storage of Sensitive Information) and CWE-319 (Cleartext Transmission of Sensitive Information). The CVSS 3.1 base score is 9.8 (Critical), with a vector of AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. All Joomla! installations from 3.9.0 to 5.4.5 and 6.0.0 to 6.1.0 are affected.
DailyCVE Form:
Platform: Joomla! CMS
Version: 3.9.0-5.4.5,
6.0.0-6.1.0
Vulnerability : Transport encryption downgrade
Severity: Critical
date: 2026-05-26
Prediction: May 26 2026
Analytics under heading What Undercode Say:
Check Force SSL setting in Joomla SELECT `value` FROM `prefix_configuration` WHERE `name` = 'force_ssl'; Simulate a vulnerable reset request (requires authentication) curl -X POST https://target.com/index.php?option=com_users&task=user.requestReset \ -d "[email protected]" -v Extract any generated http link from network logs tcpdump -i eth0 -A -s 0 'tcp port 80' | grep "reset-link" Check for existing reset tokens in logs grep -E "reset=." /var/log/nginx/access.log | grep "HTTP/1.1" Enable Force SSL via CLI in Joomla php /path/to/joomla/cli/joomla.php config:set force_ssl 2
Exploit:
An attacker first identifies a Joomla site where the “Force SSL” flag is not set. Then, they trigger a password reset for a target user (e.g., by submitting a forgotten password request). The server generates a plain `http` reset link and sends it to the user’s email. Meanwhile, the attacker runs a packet sniffer on the same network segment (e.g., tcpdump -i eth0 -A -s 0 'tcp port 80') to capture all unencrypted traffic. When the victim clicks the link, the attacker intercepts the plaintext `http` request containing the reset token. Using the captured token, the attacker visits http://target.com/reset?token=ABC123`, sets a new password, and logs in as the victim.https`. Regularly audit server logs for any `http` reset links, and consider requiring CAPTCHA or MFA for password reset attempts.
<h2 style="color: blue;">Protection:</h2>
The primary fix is to apply the vendor security patch (Joomla! update 5.4.6 / 6.1.1). As a workaround, administrators must enable the "Force SSL" flag in Global Configuration → Server tab → Force SSL → "Entire Site". Additionally, implement HSTS (HTTP Strict Transport Security) to force browsers to always use
Impact:
Successful exploitation allows a remote, unauthenticated attacker to intercept a user’s password reset link over a plaintext channel. The attacker can then take over the user’s account without any interaction from the user beyond the initial reset request. This leads to full account compromise, potential access to sensitive data, and if the compromised account has elevated privileges, a complete site takeover (including defacement, data theft, and server-level compromise). The vulnerability is particularly severe in shared hosting or public Wi-Fi environments.
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Sources:
Reported By: nvd.nist.gov
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