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Fencer Vulns
critical 9.1

CVE-2018-7544 json

A cross-protocol scripting issue was discovered in the management interface in OpenVPN through 2.4.5.

published 2018-03-16 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-19271

cvss
9.1
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.8%
EPSS 1.8% chance of exploitation in 30 days, percentile 78%
public exploits
0
none known

Summary

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

Patch / fix

  • openvpn SLE Module for Basesystem 15 SP3, SLE Module for Basesystem 15 SP2 2.4.3-5.7.1
  • openvpn SLES for SAP 12 SP5, SLES 12 SP5 2.3.8-16.26.1
  • openvpn-openssl1 SLES 11-SECURITY 2.3.2-0.10.9.1

suse advisories SUSE-SU-2021:1577-1SUSE-SU-2021:1576-1SUSE-SU-2021:14723-1

  • openvpn openSUSE Tumbleweed 2.5.4-2.1
  • openvpn openSUSE Leap 15.2 2.4.3-lp152.6.3.1

opensuse advisories openSUSE-SU-2024:11692-1openSUSE-SU-2021:0734-1

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
23 mo ago

Exploit prediction

1.79% chance of exploitation in the next 30 days, higher than 78% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • blog.0xlabs.com http://blog.0xlabs.com/2018/03/openvpn-remote-information-disclosure.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 9.1 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:P/I:N/A:P

Classification

Weakness
  • CWE-134 Use of Externally-Controlled Format String

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.