Simple Machines Forum 2.1 prior to commit 4bf35cf and 3.0 prior to commit b4d23df contains a server-side request forgery vulnerability in the image proxy that allows authenticated attackers to trigger internal HTTP requests by embedding attacker-controlled URLs in BBCode image tags, which the proxy fetches without validating resolved destination IPs against private address ranges, loopback, or link-local addresses. Attackers can leverage SMF's automatic HMAC signature generation for any embedded image URL to obtain valid signed proxy requests targeting internal services such as cloud instance metadata endpoints, internal web applications, and container network services.

Simple Machines Forum 2.1 prior to commit 7d048f8 and 3.0 prior to commit a7875e8 contains an authorization bypass vulnerability in Sources/Actions/AttachmentApprove.php where a single-character operator error causes the permission check to always pass regardless of user permissions. An authenticated low-privileged user can approve, reject, or delete any pending attachments on any board without holding the required approve_posts permission, bypass moderation queues for their own uploads, and enumerate and delete other users' pending attachments.

A vulnerability was found in SimpleMachines SMF 2.1.4. It has been classified as problematic. This affects an unknown part of the file ManageNews.php. The manipulation of the argument subject/message leads to cross site scripting. It is possible to initiate the attack remotely. The exploit has been disclosed to the public and may be used. The real existence of this vulnerability is still doubted at the moment. The vendor does not declare this issue a security vulnerability due to authentication requirements before being able to access any feature in the software that allows file modification.

A vulnerability was found in SimpleMachines SMF 2.1.4 and classified as problematic. Affected by this issue is some unknown functionality of the file ManageAttachments.php. The manipulation of the argument Notice leads to cross site scripting. The attack may be launched remotely. The exploit has been disclosed to the public and may be used. The real existence of this vulnerability is still doubted at the moment. The vendor does not declare this issue a security vulnerability due to authentication requirements before being able to access any feature in the software that allows file modification.

A vulnerability has been found in SimpleMachines SMF 2.1.4 and classified as problematic. Affected by this vulnerability is an unknown functionality of the file /index.php?action=profile;u=2;area=showalerts;do=read of the component User Alert Read Status Handler. The manipulation of the argument aid leads to improper control of resource identifiers. The attack can be launched remotely. The exploit has been disclosed to the public and may be used.

A vulnerability, which was classified as critical, was found in SimpleMachines SMF 2.1.4. Affected is an unknown function of the file /index.php?action=profile;u=2;area=showalerts;do=remove of the component Delete User Handler. The manipulation of the argument aid leads to improper control of resource identifiers. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used.