CVE-2018-7544
CVE-2018-7544 is a critical-severity vulnerability in Openvpn with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-134.
Key facts
- Severity: Critical (CVSS 3.x base score 9.1)
- CVSS v2: 6.4
- EPSS exploit prediction: 2% (77th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-134
- Affected product: Openvpn
- Published:
- Last modified:
Description
A cross-protocol scripting issue was discovered in the management interface in OpenVPN through 2.4.5. When this interface is enabled over TCP without a password, and when no other clients are connected to this interface, attackers can execute arbitrary management commands, obtain sensitive information, or cause a denial of service (SIGTERM) by triggering XMLHttpRequest actions in a web browser. This is demonstrated by a multipart/form-data POST to http://localhost:23000 with a "signal SIGTERM" command in a TEXTAREA element. NOTE: The vendor disputes that this is a vulnerability. They state that this is the result of improper configuration of the OpenVPN instance rather than an intrinsic vulnerability, and now more explicitly warn against such configurations in both the management-interface documentation, and with a runtime warning
Frequently asked questions
- What is CVE-2018-7544?
- A cross-protocol scripting issue was discovered in the management interface in OpenVPN through 2.4.5. When this interface is enabled over TCP without a password, and when no other clients are connected to this interface, attackers can execute arbitrary management commands, obtain sensitive information, or cause a denial of service (SIGTERM) by triggering XMLHttpRequest actions in a web browser. This is demonstrated by a multipart/form-data POST to http://localhost:23000 with a "signal SIGTERM" command in a TEXTAREA element. NOTE: The vendor disputes that this is a vulnerability. They state that this is the result of improper configuration of the OpenVPN instance rather than an intrinsic vulnerability, and now more explicitly warn against such configurations in both the management-interface documentation, and with a runtime warning
- How severe is CVE-2018-7544?
- CVE-2018-7544 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability high.
- Is CVE-2018-7544 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2018-7544?
- CVE-2018-7544 affects Openvpn. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2018-7544?
- 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.
- When was CVE-2018-7544 published?
- CVE-2018-7544 was published on 2018-03-16 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:openvpn:openvpn:*:*:*:*:*:*:*:*
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