CVE-2026-4962: A security flaw has been discovered in UltraVNC up to 1.6.4.0

Routine

HIGH 7.0UPGRADE

CVE-2026-4962 is a high-severity flaw (CVSS 7.0) affecting ultravnc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A security flaw has been discovered in UltraVNC up to 1.6.4.0. Affected by this issue is some unknown functionality in the library version.dll of the component Service. The manipulation results in uncontrolled search path. The attack needs to be approached locally. This attack is characterized by high complexity. The exploitation is known to be difficult. The exploit has been released to the public and may be used for attacks. The vendor was cont

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	7.0 (High)
Attack vector	Local
Attack complexity	High
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 86%)
CISA exploited list	No
Weakness	CWE-426, CWE-427
Published	2026-03-27
Last modified	2026-06-17

Publisher (CNA): VulDB · Vendor: uvnc

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-27 17:16 UTCPublished CVE record published
2026-06-17 10:57 UTCUpdated Record last modified

uvnc ultravnc UPGRADE

Affected: >= 1.6.0.0 and <= 1.6.4.0

Fixed in: newer than 1.6.4.0

Safe to downgrade to: a release before 1.6.0.0

1. Check installed version

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

2. UPGRADE to newer than 1.6.4.0 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ultravnc

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 1.6.0.0 (Debian / Ubuntu)

apt-cache madison ultravnc sudo apt install ultravnc=<VERSION_BEFORE_1.6.0.0> sudo apt-mark hold ultravnc

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

dnf --showduplicates list ultravnc sudo dnf downgrade ultravnc-<VERSION_BEFORE_1.6.0.0> sudo dnf versionlock add ultravnc

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-2026-4962?

ultravnc: upgrade to newer than 1.6.4.0. Exact commands for each OS are on this page.

Is CVE-2026-4962 being exploited?

CVE-2026-4962 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-2026-4962 affect?

CVE-2026-4962 affects ultravnc. Severity is high (CVSS 7.0). A security flaw has been discovered in UltraVNC up to 1.6.4.0. Affected by this issue is some unknown functionality in the library version.dll of the component Service. The manipulation results in uncontrolled search path. The attack needs

How urgent is CVE-2026-4962?

Priority 33/100. High severity; Public exploit reference

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References

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