CVE-2023-46849 — Using the --fragment option in certain configuration setups OpenVPN version 2

Using the --fragment option in certain configuration setups OpenVPN version 2.6.0 to 2.6.6 allows an attacker to trigger a divide by zero behaviour which could cause an application crash, leading to a denial of service.

01What is this vulnerability?

Using the --fragment option in certain configuration setups OpenVPN version 2.6.0 to 2.6.6 allows an attacker to trigger a divide by zero behaviour which could cause an application crash, leading to a denial of service.

02Affected products

Vendor	Product	Versions
OpenVPN	OpenVPN 2 (Community)	2.6.0
OpenVPN	Access Server	2.11.0, 2.12.0

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

08Timeline

• Published: 2023-11-11T00:05:13.487Z
• Last modified: 2025-06-11T14:30:02.796Z

09References

• community.openvpn.net — https://community.openvpn.net/openvpn/wiki/CVE-2023-46849
• openvpn.net — https://openvpn.net/security-advisory/access-server-security-update-cve-2023-468…
• www.debian.org — https://www.debian.org/security/2023/dsa-5555
• lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/[email protected]…
• lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/[email protected]…