CVE-2026-61520

Severity CVSS v4.0:

MEDIUM

Type:

CWE-918 Server-Side Request Forgery (SSRF)

Publication date:

14/07/2026

Last modified:

15/07/2026

Description

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&#39;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.

Impact

Vector 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N CVSS v4.0 Severity and Metrics:

Base Score: 6.30 MEDIUM
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:N/SA:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): Low
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): None
Availability (VA): None
Confidentiality (SC): High
Integrity (SI): None
Availability (SA): None

Base Score 4.0

6.30

Severity 4.0

MEDIUM

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 7.70 HIGH
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x

7.70

Severity 3.x

HIGH

CVE-2026-61520

Description

Impact

References to Advisories, Solutions, and Tools