CVE-2026-39903: SimpleMachines SMF

Simple Machines Forum Authorization Bypass via AttachmentApprove.php

CVSS 7.1 HighEPSS 0.0047 · 40th percentile

Published by the CVE Program (CNA: VulnCheck) at 10 Jul 2026, 16:03 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
SimpleMachines	SMF pkg:github/SimpleMachines/SMF	affected 2.1.0 to 2.1.7, inclusive semver unaffected 7d048f8d66aab9af51cd6ee110fbad103cf673e8 git affected 3.0.0 semver unaffected a7875e876a647572dd4c45da881b875092caac3d git Other versions: affected

Identifiers

CVE-2026-39903

CNA

VulnCheck

Weakness (CWE)

CWE-863

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
7.1	High	4.0	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N	CNA (VulnCheck)Used for this record
7.1	High	3.1	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L	CNA (VulnCheck)

CISA KEV Not listed.
EPSS 0.0047, the 40th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the CVE Program, published 10 Jul 2026. New records show when each source confirmed them.

Sources

References from the CNA

github.com/SimpleMachines/SMF/pull/9182 issue-tracking
github.com/SimpleMachines/SMF/pull/9181 issue-tracking
github.com/SimpleMachines/SMF/commit/7d048f8d66aab9af51cd6ee110fbad103cf673e8 patch
github.com/SimpleMachines/SMF/commit/a7875e876a647572dd4c45da881b875092caac3d patch
www.vulncheck.com/advisories/simple-machines-forum-authorization-bypass-via-attachmentapprove-php third-party-advisory

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.