CVE-2025-34117Router firmware OS Command Injection
A remote code execution vulnerability exists in multiple Netcore and Netis routers models with firmware released prior to August 2014 due to the presence of an undocumented backdoor listener on UDP port 53413.
Published Jul 16, 2025 · Updated Apr 14, 2026
Key Facts
Patch immediately- CVE-2025-34117 is a critical-severity vulnerability (CVSS 9.3 v4) affecting Router firmware.
- It is exploited in the wild, listed in Industry KEV feed since Mar 11, 2026. Public exploit code is available.
- EPSS estimates a 21% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v4
9.3
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/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
EPSS (30-day exploit likelihood)
21%
Higher than 97.5% of all scored CVEs
Exploit maturity
Weaponized
ATLAS score
46/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Mar 11, 2026
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Weaponized
Public exploit code
1
Proof-of-concept links
In-the-wild evidence
1
Reports of active use
Description
A remote code execution vulnerability exists in multiple Netcore and Netis routers models with firmware released prior to August 2014 due to the presence of an undocumented backdoor listener on UDP port 53413. Exact version boundaries remain undocumented. An unauthenticated remote attacker can send specially crafted UDP packets to execute arbitrary commands on the affected device.
This backdoor uses a hardcoded authentication mechanism and accepts shell commands post-authentication. Some device models include a non-standard implementation of the echo command, which may affect exploitability.
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Mar 11, 2026 | n/a | Not reported |
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Router firmware | >= Prior to August 2014 | n/a |
Timeline
Publicly disclosed
Jul 16, 2025
Added to Industry KEV feed
Mar 11, 2026
Last updated
Apr 14, 2026
Weakness Type
- CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
- CWE-306 Missing Authentication for Critical Function
- CWE-912 Hidden Functionality
References
- exploitMSF netcore_udp_53413_backdoor.rb
- exploitVulnCheck exploitation report
- otherraw.githubusercontent.com · netcore_udp_53413_backdoor.rb
- othervulners.com · MSF:EXPLOIT-LINUX-MISC-NETCORE_UDP_53413_BACKDO…
- otherweb.archive.org · netis-routers-leave-wide-open-backdoor
FAQ
Common Questions.
A remote code execution vulnerability exists in multiple Netcore and Netis routers models with firmware released prior to August 2014 due to the presence of an undocumented backdoor listener on UDP port 53413.
Affected: Router firmware versions >= Prior to August 2014. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Mar 11, 2026.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2025-34117 On Your Attack Surface?
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