ShowDoc < 2.8.7 Unauthenticated File Upload Remote Code Execution

published 2025-04-29 18 mo ago modified 2026-11-08 23 h ago also EUVD-2025-12661 , GHSA-6jmr-r7p6-f5wr

cvss: 9.4; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.4%; EPSS 2.4% chance of exploitation in 30 days, percentile 84%
public exploits: 0; none known, plus a Nuclei check

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.

Patch / fix

fixed in 2 links 1

packagist showdoc/showdoc 2.8.7
ShowDoc ShowDoc 2.8.7

github.com/star7th/showdoc#1059 pull request

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: total
Assessed: 18 mo ago (2025-04-29)

Exploit prediction

2.44% chance of exploitation in the next 30 days, higher than 84% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

Nuclei template ShowDoc - Remote Code Execution nuclei detection template
github.com https://github.com/vulhub/vulhub/tree/master/showdoc/CNVD-2020-26585 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	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
CNA	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/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

Affected packages

ecosystem	package	affected	fixed in
packagist	showdoc/showdoc	<2.8.7	2.8.7

Affected products

ShowDoc ShowDoc

Classification

Weakness

CWE-434 Unrestricted Upload of File with Dangerous Type

References

github.com /star7th/showdoc/pull/1059
issue-tracking, patch, web
github.com /vulhub/vulhub/tree/master/showdoc/CNVD-2020-26585
exploit, web
cnvd.org.cn /flaw/show/CNVD-2020-26585
third-party-advisory, web
vulncheck.com /advisories/showdoc-unauthenticated-file-upload-rce
third-party-advisory, web
nvd.nist.gov /vuln/detail/CVE-2025-0520
advisory
github.com /star7th/showdoc
package

Sources

CVE List CVE-2025-0520
GitHub Advisory GHSA-6jmr-r7p6-f5wr
NVD CVE-2025-0520

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary