CVE-2026-61520

6.3 MEDIUM 0.4% exploit odds Fix listed Disclosure Device

What it is

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.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account. Limited direct impact.
Exploit odds: 0.4% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-07-14 21:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-29 21:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.4% in the next 30 days (EPSS).
Severity: 6.3 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-07-14 21:17 UTC
Last modified: 2026-10-29 21:17 UTC
Exploit probability: 0.4% · EPSS, next 30 days
Weakness: CWE-918 · Server-side request forgery
Record status: Deferred

Attack profile CVSS 4.0 · 6.3

Attack vector: Network
Complexity: Low
Attack requirements: None
Privileges needed: Low
User interaction: None
Confidentiality: None
Integrity: None
Availability: None

Raw 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-61520.md and follow it. Check whether this project is affected by CVE-2026-61520. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record