CVE-2026-44042
3.7 · LOWOverview
CVE-2026-44042 is a low-severity vulnerability affecting uvnc ultravnc. It was published on July 1, 2026 and has a CVSS 3.1 base score of 3.7 (LOW).
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
UltraVNC repeater through 1.8.2.2 contains an off-by-one error in the Base64 decode helper used for HTTP Basic authentication. In repeater/webgui/webutils.c:817, the wi_uudecode() function checks whether the input length exceeds the output buffer with a strict greater-than comparison (>), while the correct check should be greater-than-or-equal (>=). When strlen(authdata) equals sizeof(decode), the decoded output length (approximately 3/4 of input) does not overflow the buffer in current practice because the outer HTTP request bounds constrain the Authorization header. However, the defective check leaves a latent off-by-one condition that could become exploitable if the buffering constraints change. The current risk is limited to a one-byte write at the boundary of a 1024-byte stack buffer under constrained conditions.
Remediation
Check the references section for vendor advisories and patches from uvnc. Update ultravnc to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| uvnc | ultravnc | 0 | Affected |
Frequently Asked Questions
What is CVE-2026-44042?
CVE-2026-44042 is a low-severity vulnerability affecting uvnc ultravnc. It was published on July 1, 2026 and has a CVSS 3.1 base score of 3.7 (LOW).
How severe is CVE-2026-44042?
This vulnerability has a CVSS 3.1 base score of 3.7, rated LOW. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-44042?
Check the references section for vendor advisories and patches from uvnc. Update ultravnc to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-44042?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-44042 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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