CVE-2026-35058Public exploitNetwork attack vector

Server crash via empty tls-crypt-v2 buffer assertion

Published Jun 8, 2026 · Updated Jun 8, 2026

Reachable assertion in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows remote authenticated users to crash VPN servers. tls_crypt_v2_extract_client_key() can misread the opcode as wrapped-key data or strip all remaining bytes, after which tls_crypt_unwrap() asserts that the buffer is nonempty. The server must use tls-crypt-v2, and the attacker must hold a qualifying client key or inject a packet into a live client session; the abort terminates all connected VPN sessions.

CVSS severity6.9
Medium
EPSS probability0.54%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reachable assertion in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows remote authenticated users to crash VPN servers. tls_crypt_v2_extract_client_key() can misread the opcode as wrapped-key data or strip all remaining bytes, after which tls_crypt_unwrap() asserts that the buffer is nonempty. The server must use tls-crypt-v2, and the attacker must hold a qualifying client key or inject a packet into a live client session; the abort terminates all connected VPN sessions.

The record

CVE
CVE-2026-35058
Published
Jun 8, 2026
Updated
Jun 8, 2026
Vendor
OpenVPN Inc.
Product
OpenVPN
Classifications
CWE-617, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 8, 2026Record 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=2.6.0 <=2.6.19
  2. Affected versionversion=2.7_alpha1 <=2.7.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

OpenVPN Inc. · OpenVPNversion=2.6.0 <=2.6.19; version=2.7_alpha1 <=2.7.1

Published CVSS scores

7.7Cisco TalosCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H
6.9OpenVPN Inc.CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-617Reachable Assertion
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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