---
title: "CVE-2025-0520: ShowDoc unrestricted file upload vulnerability"
url: https://erroneo.us/security/cve/CVE-2025-0520/
description: "CVE-2025-0520 (showdoc/showdoc (Composer (PHP))): An unrestricted file upload vulnerability in ShowDoc caused by improper validation of file extension…"
type: vulnerability-record
section: "Security Digest"
date_published: 2025-04-29
date_modified: 2026-10-08
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2025-0520"
kev: false
cvss: 9.4
epss: 0.02647
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2025-0520: ShowDoc unrestricted file upload vulnerability

**Signal:** Critical, preconditions apply. Severe if exploited, but exploitation needs conditions that may not apply to you. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 2.6% , percentile 85: FIRST’s model estimates a 2.6% chance of exploitation activity in the next 30 days, higher than 85% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes showdoc/showdoc (Composer (PHP)) < 2.8.7, fixed in 2.8.7 . Check your lockfile, including transitive dependencies.

## What it is

An unrestricted file upload vulnerability in ShowDoc caused by improper validation of file extension allows execution of arbitrary PHP, leading to remote code execution.This issue affects ShowDoc: before 2.8.7.

## Affected packages

- Composer (PHP) `showdoc/showdoc` < 2.8.7 → fixed: 2.8.7

## Affected products (CVE record)

- ShowDoc ShowDoc: < 2.8.7

## Severity

- VulnCheck CVSS 4.0: 9.4 `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L`
- GitHub CVSS 4.0: 9.4 `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 2.65% probability of exploitation activity in the next 30 days; percentile 85.

## Sources

- [GitHub Advisory GHSA-6jmr-r7p6-f5wr](https://github.com/advisories/GHSA-6jmr-r7p6-f5wr)
- [CVE.org record CVE-2025-0520](https://www.cve.org/CVERecord?id=CVE-2025-0520)
- [NVD entry CVE-2025-0520](https://nvd.nist.gov/vuln/detail/CVE-2025-0520)
- [github.com](https://github.com/vulhub/vulhub/tree/master/showdoc/CNVD-2020-26585)
- [github.com](https://github.com/star7th/showdoc/pull/1059)
- [cnvd.org.cn](https://www.cnvd.org.cn/flaw/show/CNVD-2020-26585)
- [vulncheck.com](https://www.vulncheck.com/advisories/showdoc-unauthenticated-file-upload-rce)

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Source page: https://erroneo.us/security/cve/CVE-2025-0520/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt