CVE-2026-35058: Improper validation of packet length during tls-crypt-v2 key extraction in OpenVPN 2.6.0 through 2.6.19 and 2.

Routine

MEDIUM 6.5UPGRADE

CVE-2026-35058 is a medium-severity flaw (CVSS 6.5) affecting openvpn. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper validation of packet length during tls-crypt-v2 key extraction in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows authenticated attackers to trigger a fatal assertion and cause a denial of service via a specially crafted packet.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-617
Published	2026-06-08
Last modified	2026-08-11

Publisher (CNA): OpenVPN Inc. · Vendor: openvpn

Last updated 2026-08-11 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-08 20:17 UTCPublished CVE record published
2026-08-11 13:11 UTCUpdated Record last modified

openvpn openvpn UPGRADE

Affected: >= 2.6.0 and < 2.6.20 · >= 2.7 and < 2.7.2

Fixed in: 2.6.20, 2.7.2

Safe to downgrade to: a release before 2.6.0

1. Check installed version

apt-cache policy openvpn || rpm -q openvpn || openvpn --version

2. UPGRADE to 2.6.20 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openvpn

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openvpn

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.6.0 (Debian / Ubuntu)

apt-cache madison openvpn sudo apt install openvpn=<VERSION_BEFORE_2.6.0> sudo apt-mark hold openvpn

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list openvpn sudo dnf downgrade openvpn-<VERSION_BEFORE_2.6.0> sudo dnf versionlock add openvpn

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-35058?

openvpn: upgrade to 2.6.20, 2.7.2. Exact commands for each OS are on this page.

Is CVE-2026-35058 being exploited?

CVE-2026-35058 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-35058 affect?

CVE-2026-35058 affects openvpn. Severity is medium (CVSS 6.5). Improper validation of packet length during tls-crypt-v2 key extraction in OpenVPN 2.6.0 through 2.6.19 and 2.7_alpha1 through 2.7.1 allows authenticated attackers to trigger a fatal assertion and cause a denial of service via a specially c

How urgent is CVE-2026-35058?

Priority 39/100. Public exploit reference

Software pages

OpenVPN vulnerabilities

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References

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