How severe is CVE-2025-0520?

No CVSS score has been assigned to CVE-2025-0520 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2025-0520?

CVE-2025-0520 affects the following packages: showdoc/showdoc (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2025-0520?

Update showdoc/showdoc to 2.8.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-0520 is resolved across your whole dependency graph.

How do I detect CVE-2025-0520 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for showdoc/showdoc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2025-0520 if there is no patch (or I can't update yet)?

Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.

Is CVE-2025-0520 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-0520 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2025-0520?

CVE-2025-0520 has an EPSS (Exploit Prediction Scoring System) score of 2.4%, placing it in the 84th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2025-0520?

CVE-2025-0520 is classified as Unrestricted File Upload (CWE-434). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

Is there exploit tooling available for CVE-2025-0520?

A Nuclei detection template exists for CVE-2025-0520, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2025-0520 published, and has it been updated?

CVE-2025-0520 was published on April 29, 2025 and was last updated on November 9, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2025-0520 — showdoc

Fix: star7th/showdoc#1059

CVE-2025-0520 is a Unrestricted File Upload vulnerability in showdoc/showdoc. A fix is available for showdoc/showdoc — see the affected versions and patch details below.

ShowDoc < 2.8.7 Unauthenticated File Upload Remote Code Execution

Also known asGHSA-6jmr-r7p6-f5wr

Published

Apr 29, 2025

Updated

Nov 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
A successful exploit gives an attacker total control of the affected component, not partial access.

Exploitation and automatability from CISA’s SSVC triage for CVE-2025-0520.

EPSS Exploitation Probability

via FIRST.org ↗

2.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs84th percentile — riskier than 84% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐘showdoc/showdoc

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

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

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`showdoc/showdoc`	all versions	2.8.7`composer require showdoc/showdoc:^2.8.7`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for showdoc/showdoc, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update showdoc/showdoc to 2.8.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-0520 is resolved across your whole dependency graph.
Workarounds
Treat uploaded files as untrusted until proven otherwise: validate the actual content type rather than the supplied extension, store uploads outside the web root on a volume mounted without execute permission, and rename them to server-generated identifiers so an attacker cannot choose the path a request will later resolve.

How to detect CVE-2025-0520

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2025-0520 -u https://target

Template: ShowDoc - Remote Code Execution
Severity: critical
Impact: The attacker does not need to go through login authentication to upload any php backdoor on the affected ShowDoc website and thereby gain server access.
Remediation: Please update ShowDoc to version 2.8.7 or higher to fix this vulnerability.

Template by ProjectDiscovery nuclei-templates (pikpikcu, Co5mos, PapButfly), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

O3 Security · Impact-Aware SCA

Is CVE-2025-0520 in your dependencies?

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