CVE-2026-61520

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.

CVSS v3 7.7 HIGH

7.7^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.1 / Impact : 4.0

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact NONE

Scope CHANGED

References

Link	Resource
https://github.com/SimpleMachines/SMF/commit/4bf35cf9e45573a5f55a6f52995086c1da89c096
https://github.com/SimpleMachines/SMF/commit/b4d23dfd74a511587c605f9d294cefc3a75b4b26
https://www.vulncheck.com/advisories/simple-machines-forum-ssrf-via-image-proxy

Configurations

No configuration.

History

14 Jul 2026, 21:17

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-07-14 21:17

Updated : 2026-07-15 21:02

NVD link : CVE-2026-61520

Mitre link : CVE-2026-61520

CVE.ORG link : CVE-2026-61520

JSON object : View

Products Affected

No product.

CWE

CWE-918

Server-Side Request Forgery (SSRF)

{"id": "CVE-2026-61520", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"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"}}], "cvssMetricV31": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"scope": "CHANGED", "version": "3.1", "baseScore": 7.7, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 4.0, "exploitabilityScore": 3.1}], "cvssMetricV40": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 6.3, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "valueDensity": "NOT_DEFINED", "vectorString": "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", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "NONE", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "disclosure@vulncheck.com", "affectedData": [{"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"}]}], "published": "2026-07-14T21:17:06.290", "references": [{"url": "https://github.com/SimpleMachines/SMF/commit/4bf35cf9e45573a5f55a6f52995086c1da89c096", "source": "disclosure@vulncheck.com"}, {"url": "https://github.com/SimpleMachines/SMF/commit/b4d23dfd74a511587c605f9d294cefc3a75b4b26", "source": "disclosure@vulncheck.com"}, {"url": "https://www.vulncheck.com/advisories/simple-machines-forum-ssrf-via-image-proxy", "source": "disclosure@vulncheck.com"}], "vulnStatus": "Deferred", "weaknesses": [{"type": "Secondary", "source": "disclosure@vulncheck.com", "description": [{"lang": "en", "value": "CWE-918"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-07-15T21:02:41.590", "sourceIdentifier": "disclosure@vulncheck.com"}