CVE-2025-34117
CVE-2025-34117 is a critical-severity vulnerability with a CVSS 4.0 base score of 9.3. Its EPSS exploit-prediction score of 23% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-78.
Key facts
- Severity: Critical (CVSS 4.0 base score 9.3)
- EPSS exploit prediction: 23% (97th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-21753
- Weakness: CWE-78
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2025-34117?
- 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.
- How severe is CVE-2025-34117?
- CVE-2025-34117 has a CVSS 4.0 base score of 9.3, rated critical severity.
- Is CVE-2025-34117 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 23% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2025-34117?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2025-34117 have an EU (EUVD) identifier?
- Yes. CVE-2025-34117 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-21753.
- When was CVE-2025-34117 published?
- CVE-2025-34117 was published on 2025-07-16 and last updated on 2026-06-17.
References
- https://raw.githubusercontent.com/rapid7/metasploit-framework/master/modules/exploits/linux/misc/netcore_udp_53413_backdoor.rb
- https://vulners.com/metasploit/MSF:EXPLOIT-LINUX-MISC-NETCORE_UDP_53413_BACKDOOR-
- https://web.archive.org/web/20140828114943/http://blog.trendmicro.com/trendlabs-security-intelligence/netis-routers-leave-wide-open-backdoor/
- https://www.exploit-db.com/exploits/43387
- https://www.seebug.org/vuldb/ssvid-90227
- https://www.shadowserver.org/what-we-do/network-reporting/netcore-netis-router-vulnerability-scan-report/
- https://www.vulncheck.com/advisories/netcore-netis-routers-backdoor-rce
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