How severe is CVE-2025-34037?

No CVSS score has been assigned to CVE-2025-34037 yet. Review the advisory details and affected package list to assess your exposure.

Which products are affected by CVE-2025-34037?

CVE-2025-34037 affects the following products: Linksys E4200, Linksys E3200, Linksys E3000, Linksys E2500 v1/v2, Linksys E2100L v1, Linksys E1550, Linksys E1500 v1, Linksys E1200 v1, and 2 more.

How do I patch CVE-2025-34037?

Apply the Linksys E4200 security patch or hotfix for CVE-2025-34037 on the affected version, following the vendor advisory for your exact build.

How do I detect CVE-2025-34037 across my infrastructure?

Inventory every Linksys E4200 deployment and check each version against the affected-products list above.

How do I mitigate CVE-2025-34037 if there is no patch (or I can't update yet)?

Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Is CVE-2025-34037 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-34037 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-2025-34037?

CVE-2025-34037 has an EPSS (Exploit Prediction Scoring System) score of 96.2%, placing it in the 100th 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. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2025-34037?

CVE-2025-34037 is classified as OS Command Injection (CWE-78). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Which products and versions are affected by CVE-2025-34037?

CVE-2025-34037 affects Linksys E4200 (1 version, e.g. 0); Linksys E3200 (1 version, e.g. 0); Linksys E3000 (1 version, e.g. 0); Linksys E2500 v1/v2 (1 version, e.g. 0), and 6 more product(s). Check the affected-products list on this page against your deployed version to confirm exposure.

When was CVE-2025-34037 published, and has it been updated?

CVE-2025-34037 was published on June 24, 2025 and was last updated on July 22, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2025-34037: E4200 Command Injection

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.
CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
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-2025-34037.

EPSS Exploitation Probability

via FIRST.org ↗

96.2%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs100th percentile — riskier than 100% of all scored CVEsHighest risk

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

Description

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.

Affected Products

10 products · 10 configurations

Application

E4200Linksys

< 1.0.06

1 version

0

Application

E3200Linksys

< 1.0.05

1 version

0

Application

E3000Linksys

< 1.0.06

1 version

0

Application

E2500 v1/v2Linksys

< 2.0.00

1 version

0

Application

E2100L v1Linksys

≤ 1.0.05

1 version

0

Application

E1550Linksys

≤ 1.0.03

1 version

0

Detection & mitigation playbook

Vendor / appliance

Detect
Inventory every Linksys E4200 deployment and check each version against the affected-products list above.
Fix
Apply the Linksys E4200 security patch or hotfix for CVE-2025-34037 on the affected version, following the vendor advisory for your exact build.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.

Frequently Asked Questions

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 limit

O3 Security · Runtime Protection

Is CVE-2025-34037 being exploited in your environment?

Detect and block the exploit chain at execution, on systems you cannot patch yet.

Protect my workloads How runtime protection works

CVE-2025-34037 — E4200

Exploitation Status

Proof-of-concept exploit code exists

EPSS Exploitation Probability

Description

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2025-34037 being exploited in your environment?