OpenVPN: Buffer Over-read
CVE-2025-12106 is a critical-severity buffer over-read vulnerability in OpenVPN, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected OpenVPN versions: 2.7_alpha1 through 2.7_rc1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.58% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of OpenVPN you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on community.openvpn.net for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H. Scored by CISA (ADP).
Official description
Insufficient argument validation in OpenVPN 2.7_alpha1 through 2.7_rc1 allows an attacker to trigger a heap buffer over-read when parsing IP addresses
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Buffer Over-read
The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
- mail-archive.com/[email protected]/msg00152.htmlMailing List
Other vulnerabilities in OpenVPN
- 7.2 High severity
- 7.1 High severity
- 8.7 High severity
- 7.7 High severity
- 8.5 High severity
- 9.1 Critical severity
Recent Buffer Over-read vulnerabilities
- 7.3 High severity
- 7.5 High severity
- 7.5 High severity
- 7.8 High severity
- 8.2 High severity
- 7.1 High severity
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