How severe is CVE-2026-44041?

CVE-2026-44041 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.

Is CVE-2026-44041 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-44041?

CVE-2026-44041 affects Uvnc Ultravnc. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-44041?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2026-44041 published?

CVE-2026-44041 was published on 2026-07-01 and last updated on 2026-07-02.

CVE-2026-44041

CVE-2026-44041 is a medium-severity vulnerability in Uvnc Ultravnc with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 0% (17th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-125
Affected product: Uvnc Ultravnc
Published: 2026-07-01
Last modified: 2026-07-02

Description

UltraVNC through 1.8.2.2 contains an out-of-bounds read in the wide-string to multibyte conversion helper. In rfb/dh.cpp:204, the vncWc2Mb() function passes a caller-supplied WCHAR pointer to wcslen() before any bounds check. If the caller provides a wide-character buffer that is not properly NUL-terminated, wcslen() reads past the end of the buffer until it encounters a NUL wchar, resulting in an out-of-bounds read. Under typical Win32 API usage this requires an abnormal caller contract. Impact is limited to a potential information disclosure from adjacent memory regions or a process crash (denial of service) if the over-read crosses a page boundary.

Frequently asked questions

What is CVE-2026-44041?: UltraVNC through 1.8.2.2 contains an out-of-bounds read in the wide-string to multibyte conversion helper. In rfb/dh.cpp:204, the vncWc2Mb() function passes a caller-supplied WCHAR pointer to wcslen() before any bounds check. If the caller provides a wide-character buffer that is not properly NUL-terminated, wcslen() reads past the end of the buffer until it encounters a NUL wchar, resulting in an out-of-bounds read. Under typical Win32 API usage this requires an abnormal caller contract. Impact is limited to a potential information disclosure from adjacent memory regions or a process crash (denial of service) if the over-read crosses a page boundary.
How severe is CVE-2026-44041?: CVE-2026-44041 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability low.
Is CVE-2026-44041 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (17th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-44041?: CVE-2026-44041 affects Uvnc Ultravnc. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-44041?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2026-44041 published?: CVE-2026-44041 was published on 2026-07-01 and last updated on 2026-07-02.

References

Affected products (1)

cpe:2.3:a:uvnc:ultravnc:*:*:*:*:*:*:*:*

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