CVE-2026-39903 (GCVE-0-2026-39903)
Vulnerability from cvelistv5 – Published: 2026-07-10 16:03 – Updated: 2026-07-28 01:48 X_Open Source
VLAI
EPSS
VEX
Title
Simple Machines Forum Authorization Bypass via AttachmentApprove.php
Summary
Simple Machines Forum 2.1 prior to commit 7d048f8 and 3.0 prior to commit a7875e8 contains an authorization bypass vulnerability in Sources/Actions/AttachmentApprove.php where a single-character operator error causes the permission check to always pass regardless of user permissions. An authenticated low-privileged user can approve, reject, or delete any pending attachments on any board without holding the required approve_posts permission, bypass moderation queues for their own uploads, and enumerate and delete other users' pending attachments.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-14 01:56 UTC
CWE
- CWE-863 - Incorrect Authorization
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://github.com/SimpleMachines/SMF/pull/9182 | issue-tracking |
| https://github.com/SimpleMachines/SMF/pull/9181 | issue-tracking |
| https://github.com/SimpleMachines/SMF/commit/7d04… | patch |
| https://github.com/SimpleMachines/SMF/commit/a787… | patch |
| https://www.vulncheck.com/advisories/simple-machi… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| SimpleMachines | SMF |
Affected:
2.1.0 , ≤ 2.1.7
(semver)
Unaffected: 7d048f8d66aab9af51cd6ee110fbad103cf673e8 (git) Affected: 3.0.0 (semver) Unaffected: a7875e876a647572dd4c45da881b875092caac3d (git) cpe:2.3:a:simplemachines:simple_machines_forum:*:*:*:*:*:*:*:* cpe:2.3:a:simplemachines:simple_machines_forum:3.0.0:*:*:*:*:*:*:* |
Date Public
2026-04-07 00:00
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| Author | Source | Type | Date | Other |
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Nomenclature
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Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.