What is CVE-2025-34037?
An OS command injection vulnerability exists in various models of E-Series Linksys routers via the /tmUnblock.cgi and /hndUnblock.cgi endpoints over HTTP on port 8080. The CGI scripts improperly process user-supplied input passed to the ttcp_ip parameter without sanitization, allowing unauthenticated attackers to inject shell commands. This vulnerability was reported to be exploited in the wild by the "TheMoon" worm in 2014 to deploy a MIPS ELF payload, enabling arbitrary code execution on the router. Additionally, this vulnerability may affect other Linksys products to include, but not limited to, WAG/WAP/WES/WET/WRT-series router models and Wireless-N access points and routers. Exploitation evidence was observed by the Shadowserver Foundation on 2025-02-06 UTC.
The record classifies CVE-2025-34037 under weakness class CWE-78. 11 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 487 days ago.
Severity and exploitation probability
- CVSS v4.0 base score
- 10 — Critical (derived from score)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H - EPSS (FIRST)
- 92.7% probability of exploitation in the next 30 days, higher than 99.8% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 10/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2025-06-24, last modified 2026-07-22
Is CVE-2025-34037 being exploited?
Weaponised exploit code for CVE-2025-34037 is publicly available. 2 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 43 in the Threadlinqs vulnerability feed.
- Taxanehh/CVE-2025-34037 (github)
- trickest/cve (trickest)
Affected products and versions
- Linksys: E4200, E3200, E3000, E2500 v1/v2, E2100L v1, E2000, E1550, E1500 v1, E1200 v1, E1000 v1, E900 v1
How to fix CVE-2025-34037
No vendor patch reference has been recorded for CVE-2025-34037 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2025-34037
3 tracked threats in the Threadlinqs corpus reference CVE-2025-34037, either in the campaign’s CVE list or as an indicator on the campaign record.
- ClingSTUN Linux Backdoor Turns Unpatched IoT Devices Into Proxy Nodes via Public STUN Infrastructure — HIGH · 2026-10-05
- Cling IoT botnet masquerades as Google STUN traffic for C2, exploiting Realtek Jungle SDK CVE-2021-35394 — CRITICAL · 2026-10-03
- TuxBot v3 Evolution: LLM-Assisted IoT Botnet Framework With a Broken Multi-CVE Exploit Chain — HIGH · 2026-07-15
Sources
Enriched from CVE.org, NVD, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.