# CVE-2026-84423 — Casdoor

> As of 2026-09-01, CVE-2026-84423 is a HIGH-severity vulnerability in Casdoor, CVSS v3.1 7.3, EPSS 0.4% (33.2th percentile). No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-84423 as of 2026-09-01; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-09-01

## What is CVE-2026-84423?

A vulnerability has been found in Casdoor up to 4.0.0. This affects an unknown function of the file controllers/resource.go of the component upload-resource API. Such manipulation leads to missing authentication. It is possible to launch the attack remotely. The exploit has been disclosed to the public and may be used. The vendor deleted the GitHub issue for this vulnerability without any explanation. Afterwards the vendor was contacted early about this disclosure via email but did not respond in any way.

The record classifies CVE-2026-84423 under weakness classes [CWE-306](https://intel.threadlinqs.com/cwe/CWE-306), [CWE-287](https://intel.threadlinqs.com/cwe/CWE-287). Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 34 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 7.3 — HIGH (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R`)
- **CVSS v4.0 base score:** 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P`)
- **EPSS (FIRST):** 0.4% probability of exploitation in the next 30 days, higher than 33.2% of all scored CVEs
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-01

## Is CVE-2026-84423 being exploited?

It currently carries a trending score of 38 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **(vendor unspecified)**: Casdoor

## How to fix CVE-2026-84423

No vendor patch reference has been recorded for CVE-2026-84423 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-84423

No threat campaign in the Threadlinqs corpus currently references CVE-2026-84423, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, GitHub Security Advisories, FIRST EPSS. Last verified by Threadlinqs on 2026-09-03.

**Exploit and proof of concept**

- [github.com — exploit](https://github.com/geo-chen/oss/blob/main/casdoor.md#finding-1-unauthenticated-arbitrary-file-upload-via-apiupload-resource)

**Third-party advisory**

- [vuldb.com — signature](https://vuldb.com/vuln/397791/cti)
- [vuldb.com — third party advisory](https://vuldb.com/cve/CVE-2026-84423)
- [vuldb.com — third party advisory (883037)](https://vuldb.com/submit/883037)

**Vulnerability database entry**

- [vuldb.com — vdb entry](https://vuldb.com/vuln/397791)

**Issue tracking and product pages**

- [github.com — issue tracking](https://github.com/casdoor/casdoor/issues/5617)
- [github.com — product](https://github.com/casdoor/casdoor/)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-84423
Full detection coverage and IOCs for threats exploiting CVE-2026-84423 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp