CVE-2026-61520
Simple Machines Forum SSRF via image proxy
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.
INFO
Published Date :
July 14, 2026, 9:17 p.m.
Last Modified :
Oct. 29, 2026, 9:17 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-61520
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Simple Machines Forum to a fixed version.
- Apply the latest security patches.
- Validate image proxy destination IPs.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-61520.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-61520 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-61520
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-61520 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-61520 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by [email protected]
Oct. 29, 2026
Action Type Old Value New Value Changed 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. Added Affected Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/61xxx/CVE-2026-61520.json">CVE-2026-61520</a> Added Reference https://github.com/SimpleMachines/SMF/commit/4bf35cf9e45573a5f55a6f52995086c1da89c096 Added Reference https://github.com/SimpleMachines/SMF/commit/b4d23dfd74a511587c605f9d294cefc3a75b4b26 Added Reference https://www.vulncheck.com/advisories/simple-machines-forum-ssrf-via-image-proxy Removed Reference https://github.com/SimpleMachines/SMF/commit/4bf35cf9e45573a5f55a6f52995086c1da89c096 Removed Reference https://github.com/SimpleMachines/SMF/commit/b4d23dfd74a511587c605f9d294cefc3a75b4b26 Removed Reference https://www.vulncheck.com/advisories/simple-machines-forum-ssrf-via-image-proxy -
CVE Translated by [email protected]
Oct. 24, 2026
Action Type Old Value New Value Added Translation Title: SMF de SimpleMachines, Description: Simple Machines Forum 2.1 anterior al commit 4bf35cf y 3.0 anterior al commit b4d23df contiene una vulnerabilidad de falsificación de petición del lado del servidor en el proxy de imágenes que permite a atacantes autenticados activar peticiones HTTP internas incrustando URLs controladas por el atacante en etiquetas de imagen BBCode, las cuales el proxy obtiene sin validar las IPs de destino resueltas contra rangos de direcciones privadas, loopback o direcciones link-local. Los atacantes pueden aprovechar la generación automática de firmas HMAC de SMF para cualquier URL de imagen incrustada para obtener peticiones de proxy firmadas válidas dirigidas a servicios internos como puntos finales de metadatos de instancias en la nube, aplicaciones web internas y servicios de red de contenedores. -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 15, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-61520', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-15T13:20:14.309005Z'} -
CVE Modified by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Changed Affected [{'repo': 'https://github.com/SimpleMachines/SMF', 'vendor': 'SimpleMachines', 'product': 'SMF', 'versions': [{'status': 'affected', 'version': '2.1.0', 'lessThan': '2.1.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '4bf35cf9e45573a5f55a6f52995086c1da89c096', 'versionType': 'git'}, {'status': 'unaffected', 'version': '3.0.0', 'versionType': 'semver'}, {'status': 'affected', 'version': 'b4d23dfd74a511587c605f9d294cefc3a75b4b26', 'versionType': 'git'}], 'defaultStatus': 'affected'}] [{'repo': 'https://github.com/SimpleMachines/SMF', 'vendor': 'SimpleMachines', 'product': 'SMF', 'versions': [{'status': 'affected', 'version': '2.1.0', 'lessThan': '2.1.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '4bf35cf9e45573a5f55a6f52995086c1da89c096', 'versionType': 'git'}, {'status': 'unaffected', 'version': '3.0.0', 'versionType': 'semver'}, {'status': 'affected', 'version': 'b4d23dfd74a511587c605f9d294cefc3a75b4b26', 'versionType': 'git'}], 'packageURL': 'pkg:github/SimpleMachines/SMF', 'defaultStatus': 'affected'}] -
New CVE Received by [email protected]
Jul. 14, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/SimpleMachines/SMF', 'vendor': 'SimpleMachines', 'product': 'SMF', 'versions': [{'status': 'affected', 'version': '2.1.0', 'lessThan': '2.1.7', 'versionType': 'semver'}, {'status': 'unaffected', 'version': '4bf35cf9e45573a5f55a6f52995086c1da89c096', 'versionType': 'git'}, {'status': 'unaffected', 'version': '3.0.0', 'versionType': 'semver'}, {'status': 'affected', 'version': 'b4d23dfd74a511587c605f9d294cefc3a75b4b26', 'versionType': 'git'}], 'defaultStatus': 'affected'}] 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. Added CVSS V4.0 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 Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N Added CWE CWE-918 Added Reference https://github.com/SimpleMachines/SMF/commit/4bf35cf9e45573a5f55a6f52995086c1da89c096 Added Reference https://github.com/SimpleMachines/SMF/commit/b4d23dfd74a511587c605f9d294cefc3a75b4b26 Added Reference https://www.vulncheck.com/advisories/simple-machines-forum-ssrf-via-image-proxy