Is CVE-2026-44042 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-44042 being exploited in the wild.

How severe is CVE-2026-44042?

Low severity, with a CVSS score of 3.7, published 1 July 2026.

Which products and versions are affected?

UltraVNC Repeater through 1.8.2.2.

Is there a fix for CVE-2026-44042?

No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

How is CVE-2026-44042 attacked?

It is attacked over the network, in a network appliance.

Am I affected by CVE-2026-44042?

Check whether you run UltraVNC Repeater at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-44042: UltraVNC Repeater off-by-one error in HTTP Basic authentication

CVE-2026-44042 · Severity: low · CVSS 3.7 · Published 2026-07-01

UltraVNC Repeater, a tool used to facilitate remote desktop connections through firewalls, contains a minor technical flaw in how it handles login credentials for its web management interface. An attacker could potentially cause a small, controlled memory error by sending a specially crafted login request. While currently difficult to exploit for any significant harm, this flaw represents a latent security risk that could be used to disrupt the service if other system conditions change.

Technologies: UltraVNC Repeater. Vendors: UltraVNC.

Quick answers

Is CVE-2026-44042 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-44042 being exploited in the wild.
How severe is CVE-2026-44042?: Low severity, with a CVSS score of 3.7, published 1 July 2026.
Which products and versions are affected?: UltraVNC Repeater through 1.8.2.2.
Is there a fix for CVE-2026-44042?: No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-44042 attacked?: It is attacked over the network, in a network appliance.
Am I affected by CVE-2026-44042?: Check whether you run UltraVNC Repeater at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

An off-by-one error exists in the wi_uudecode() function within repeater/webgui/webutils.c:817. The function utilizes a strict greater-than (>) comparison instead of greater-than-or-equal (>=) when validating if the input length exceeds the output buffer size. This flaw can be triggered via the Authorization header during HTTP Basic authentication. While current HTTP request bounds typically prevent a full buffer overflow, the defect allows a one-byte write at the boundary of a 1024-byte stack buffer. This is considered a latent vulnerability that could lead to a denial of service or limited memory corruption if buffering constraints are modified in future versions.

Affected products

UltraVNC UltraVNC Repeater through 1.8.2.2

Timeline

2026-07-01: disclosed
2026-07-01: advisory

References

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