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  4. CVE 2026 44041 ultravnc vncwc2mb calls wcslen before validating
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Back to active CVEs
Medium · CVSS 4.3CVE-2026-44041

UltraVNC vncWc2Mb calls wcslen() before validating that the wide string is NUL-terminatedCVE-2026-44041

Answer in brief

CVE-2026-44041 records a Medium severity (CVSS 4.3) vulnerability in UltraVNC vncWc2Mb calls wcslen() before validating that the wide string is NUL-terminated. The current sources do not mark it as known exploited. The current feed maps uvnc/UltraVNC (generic), uvnc/UltraVNC (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jul 1, 2026Updated Oct 25, 2026Source checked Nov 4, 2026First seen by HOL Jul 1, 2026Material review Oct 25, 2026
Upstream Advisory

Key facts

Risk
Medium · CVSS 4.3
Exploitation
Not marked as known exploited
Affected software
3 mapped packages or products
Fix availability
Not reported

Why this deserves its current priority

CVSS is 4.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps uvnc/UltraVNC (generic), uvnc/UltraVNC (generic). Check affected ranges and fixed versions before updating.

Affected products and reported versions
ProductAffected versionsFixed versions
cpe:2.3:a:uvnc:ultravnc:*:*:*:*:*:*:*:*Not reportedNot reported
Mapped affected packages and fixed versions
PackageAffected rangeFixed version
uvnc/UltraVNCgeneric0Not reported
uvnc/UltraVNCgeneric>=0 <=1.8.2.2Not reported

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for uvnc/UltraVNC, uvnc/UltraVNC.
  2. 2Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

  1. Published upstream

    Jul 1, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Oct 25, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Jul 1, 2026

Sources and claim methodology

  • GitHub security advisorygithub.com
  • Source referenceuvnc.com
  • Source referencesecurin.io
Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Mongoose: Heap OOB reads and null-byte bypass in mg_path_is_sane (util.c)Also CWE-125
  • VeraCrypt: Heap overflow and out-of-bounds read in Serializable deserialization (elevated Core service input path)Also CWE-125

Record context

Vulnerability class
Buffer Overflow
EPSS
Not reported
CWE IDs
CWE-125
Source
CVE List V5
Source checked
Nov 4, 2026
References
3 linked sources
Open source record