CVE-2026-61520

Simple Machines Forum SSRF via image proxy

HIGH
7.7
CVSS Score
Published: July 14, 2026 at 08:17 PM UTC
Updated: October 24, 2026 at 09:10 PM UTC
2 products affected across 1 vendorSimple Machines ForumSMF

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Severity
HIGH7.7
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

2.1.0 ≤ v < 2.1.7
Affected range stops below 2.1.7, so it looks safe — our inference, not a vendor statement
2.1.0 ≤ v < 2.1.72.1.0b4d23dfd74a511587c605f9d294cefc3a75b4b26
Affected range stops below 2.1.7, so it looks safe — our inference, not a vendor statement
Vendor states this is fixed in 3.0.0 (unaffected)
Vendor states this is fixed in 4bf35cf9e45573a5f55a6f52995086c1da89c096 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.7HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-918

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