CVE-2026-12996: A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote authenticated peer

This month

HIGH 8.1WATCHLISTUPGRADEMITIGATE

CVE-2026-12996 is a high-severity flaw (CVSS 8.1) affecting openvpn, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote authenticated peers to potentially cause a denial of service or leak memory via crafted packets during TLS session promotion or expiry

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.5% (top 60%)
CISA exploited list	No
Weakness	CWE-125, CWE-416
Published	2026-07-30
Last modified	2026-08-05

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

Last updated 2026-08-05 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-30 17:16 UTCPublished CVE record published
2026-08-05 19:38 UTCUpdated Record last modified

openvpn openvpn UPGRADE

Affected: >= 2.6.0 and < 2.6.21 · >= 2.7 and < 2.7.5

Fixed in: 2.6.21, 2.7.5

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 2.6.21 (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.

debian debian linux MITIGATE

Affected: 11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 11.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2026-12996?

openvpn: upgrade to 2.6.21, 2.7.5; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-12996 being exploited?

CVE-2026-12996 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-2026-12996 affect?

CVE-2026-12996 affects openvpn, debian linux. Severity is high (CVSS 8.1). A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote authenticated peers to potentially cause a denial of service or leak memory via crafted packets during TLS session promotion or expiry

How urgent is CVE-2026-12996?

Priority 43/100. High severity; On your watchlist

Software pages

Debian vulnerabilities · OpenVPN vulnerabilities

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References

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