CVE-2023-46849Public exploitNetwork attack vector

Service crash via unrestored fragment sizing state

Published Nov 11, 2023 · Updated Jun 11, 2025

Divide-by-zero in affected OpenVPN and Access Server releases allows remote attackers to crash a fragment-enabled VPN service on reconnect. Reconnect handling restores the --fragment option without recalculating max_fragment_size, leaving optimal_fragment_size to divide by zero. The flaw requires a non-default --fragment configuration; it interrupts the VPN process without reported data disclosure or modification.

CVSS severity7.5
High
EPSS probability1.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Divide-by-zero in affected OpenVPN and Access Server releases allows remote attackers to crash a fragment-enabled VPN service on reconnect. Reconnect handling restores the --fragment option without recalculating max_fragment_size, leaving optimal_fragment_size to divide by zero. The flaw requires a non-default --fragment configuration; it interrupts the VPN process without reported data disclosure or modification.

The record

CVE
CVE-2023-46849
Published
Nov 11, 2023
Updated
Jun 11, 2025
Vendor
OpenVPN Inc.
Product
OpenVPN Access Server
Classifications
CWE-369, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Nov 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Jun 11, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.11.0 <=2.11.3
  2. Affected versionversion=2.12.0 <=2.12.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenVPN Inc. · OpenVPN Access Serverversion=2.11.0 <=2.11.3; version=2.12.0 <=2.12.1
OpenVPN Inc. · OpenVPNversion=2.6.0 <=2.6.6

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-369Divide By Zero
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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