CVE-2025-0520
published 2025-04-29CVE-2025-0520: An unrestricted file upload vulnerability in ShowDoc caused by improper validation of file extension allows execution of arbitrary PHP, leading to remote code…
PriorityP183critical9.4CVSS 4.0
AVNACLATNPRLUINVCHVIHVALSCHSIHSALEXCRXIRXARXMAVXMACXMATXMPRXMUIXMVCXMVIXMVAXMSCXMSIXMSAXSXAUXRXVXREXUX
ITWVulnCheck KEV
Exploited in the wild
EPSS
0.98%
57.7th percentile
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
2 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| showdoc | showdoc | < 2.8.7 | 2.8.7 |
| showdoc | showdoc | >= 0 < 2.8.7 | 2.8.7 |
Detection & IOCsextracted from sources · hover to see the quote
otherCVE-2025-0520 / CNVD-2020-26585 unrestricted unauthenticated file upload leading to web shell upload↗
- →Monitor for PHP web shell file uploads to ShowDoc instances — the exploit involves uploading arbitrary PHP files via the unauthenticated file upload endpoint due to improper file extension validation. ↗
- →Flag unauthenticated HTTP requests that upload .php files to ShowDoc endpoints; exploitation does not require authentication. ↗
- →Identify ShowDoc instances running versions prior to 2.8.7 in your environment; over 2,000 internet-exposed instances exist, predominantly in China, and active exploitation against honeypots has been confirmed. ↗
- ·This is an N-day vulnerability (patched since 2020) now under active exploitation for the first time; unpatched legacy deployments remain at risk. ↗
CVSS provenance
nvdv4.09.4CRITICALCVSS: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
vulncheck9.4CRITICAL
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GHSA
ShowDoc unrestricted file upload vulnerability
ghsa·2025-04-29
CVE-2025-0520 [CRITICAL] CWE-434 ShowDoc unrestricted file upload vulnerability
ShowDoc unrestricted file upload vulnerability
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.
OSV
ShowDoc unrestricted file upload vulnerability
osv·2025-04-29
CVE-2025-0520 [CRITICAL] ShowDoc unrestricted file upload vulnerability
ShowDoc unrestricted file upload vulnerability
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.
VulnCheck
showdoc showdoc Unrestricted Upload of File with Dangerous Type
vulncheck·2025·CVSS 9.4
CVE-2025-0520 [CRITICAL] showdoc showdoc Unrestricted Upload of File with Dangerous Type
showdoc showdoc Unrestricted Upload of File with Dangerous Type
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: showdoc showdoc
Required Action: Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.
Exploitation References: https://api.vulncheck.com/v3/index/vulncheck-canaries?cve=CVE-2025-0520&date=2026-04-10
No detection rules found.
No public exploits indexed.
Hackernews
⚡ Weekly Recap: Vercel Hack, Push Fraud, QEMU Abused, New Android RATs Emerge & More
blogs_hackernews·2026-04-20
CVE-2026-20184 ⚡ Weekly Recap: Vercel Hack, Push Fraud, QEMU Abused, New Android RATs Emerge & More
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## ⚡ Weekly Recap: Vercel Hack, Push Fraud, QEMU Abused, New Android RATs Emerge & More
Monday’s recap shows the same pattern in different places. A third-party tool becomes a way in, then leads to internal access. A trusted download path is briefly swapped to deliver malware. Browser extensions act normally while pulling data and running code. Even update channels are used to push payloads. It’s not breaking systems—it’s bending trust.
There’s also a shift in how attacks run. Slower check-ins, multi-stage payloads, andmore code kept in memory. Attackers lean on real tools and normal workflows instead of custom builds. Some cas
Hackernews
ShowDoc RCE Flaw CVE-2025-0520 Actively Exploited on Unpatched Servers
blogs_hackernews·2026-04-14·CVSS 9.4
CVE-2025-0520 [CRITICAL] ShowDoc RCE Flaw CVE-2025-0520 Actively Exploited on Unpatched Servers
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## ShowDoc RCE Flaw CVE-2025-0520 Actively Exploited on Unpatched Servers
A critical security vulnerability impacting ShowDoc , a document management and collaboration service popular in China, has come under active exploitation in the wild.
The vulnerability in question is CVE-2025-0520 (aka CNVD-2020-26585), which carries a CVSS score of 9.4 out of 10.0.
It relates to a case of unrestricted file upload that stems from improper validation of file extension, allowing an attacker to upload arbitrary PHP files and achieve remote code execution.
"[In] ShowDoc version before 2.8.7, an unrestricted and unauthenticated file upload
Greynoiseio
NoiseLetter January 2025
blogs_greynoiseio
NoiseLetter January 2025
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2025-04-29
Published
Exploited in the wild