CVE-2026-61520

Simple Machines Forum SSRF via image proxy

Published Jul 14, 2026 CVSS 4.0 · 6.3 Medium EPSS < 1% KEV · Not listed
Description
Simple Machines Forum 2.1 prior to commit b4d23df (fixed in 2.1.8) and 3.0 prior to commit 4bf35cf 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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
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'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 b4d23df (fixed in 2.1.8) and 3.0 prior to commit 4bf35cf 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.
CPEs cpe:2.3:a:simplemachines:simple_machines_forum:3.0:alpha1:*:*:*:*:*:*
cpe:2.3:a:simplemachines:simple_machines_forum:3.0:alpha2:*:*:*:*:*:*
cpe:2.3:a:simplemachines:simple_machines_forum:3.0:alpha3:*:*:*:*:*:*
cpe:2.3:a:simplemachines:simple_machines_forum:3.0:alpha4:*:*:*:*:*:*
Type Values Removed Values Added
First Time appeared Simplemachines simple Machines Forum
CPEs cpe:2.3:a:simplemachines:simple_machines_forum:*:*:*:*:*:*:*:*
Vendors & Products Simplemachines simple Machines Forum
Type Values Removed Values Added
First Time appeared Simplemachines
Simplemachines smf
Vendors & Products Simplemachines
Simplemachines smf
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
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'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.
Title Simple Machines Forum SSRF via image proxy
Weaknesses CWE-918
References
Metrics cvssV3_1

{'score': 7.7, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N'}

cvssV4_0

{'score': 6.3, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 29, 2026, 9:16 PM
Reserved
Jul 10, 2026, 3:43 PM
Status
Deferred
Published
Jul 14, 2026, 9:17 PM
Modified
Oct 29, 2026, 9:17 PM