{"id":"CVE-2026-44041","state":"PUBLISHED","title":"UltraVNC vncWc2Mb calls wcslen() before validating that the wide string is NUL-terminated","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.","publishedAt":"2026-07-01T03:33:19.127Z","updatedAt":"2026-07-09T04:36:09.188Z","severity":{"score":4.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","source":"securin"},"assigner":"securin","products":["uvnc UltraVNC"],"affected":[{"vendor":"uvnc","product":"UltraVNC","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"1.8.2.2","versionType":"custom"}],"modules":["winvnc","vncviewer"]}],"references":["https://uvnc.com/","https://github.com/ultravnc/UltraVNC","https://www.securin.io/zero-days/cve-2026-44041-vncwc2mb-wcslen-before-bounds-check-ultravnc"],"weaknesses":["CWE-125"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/44xxx/CVE-2026-44041.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-44041","state":"PUBLISHED","datePublished":"2026-07-01T03:33:19.127Z","dateUpdated":"2026-07-09T04:36:09.188Z","assignerShortName":"securin","assignerOrgId":"33c584b5-0579-4c06-b2a0-8d8329fcab9c","dateReserved":"2026-05-05T03:40:37.003Z"},"containers":{"cna":{"title":"UltraVNC vncWc2Mb calls wcslen() before validating that the wide string is NUL-terminated","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"uvnc","product":"UltraVNC","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThanOrEqual":"1.8.2.2","versionType":"custom"}],"modules":["winvnc","vncviewer"]}],"references":[{"url":"https://uvnc.com/","name":"UltraVNC project page","tags":["vendor-advisory"]},{"url":"https://github.com/ultravnc/UltraVNC","name":"UltraVNC source repository","tags":["product"]},{"url":"https://www.securin.io/zero-days/cve-2026-44041-vncwc2mb-wcslen-before-bounds-check-ultravnc"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW","baseScore":4.3,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-125","type":"CWE","lang":"en","description":"Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"securin","orgId":"33c584b5-0579-4c06-b2a0-8d8329fcab9c","dateUpdated":"2026-07-09T04:36:09.188Z"},"timeline":[{"time":"2026-06-02T00:00:00.000Z","lang":"en","value":"Vulnerability discovered during security audit"},{"time":"2026-06-17T00:00:00.000Z","lang":"en","value":"Reported to vendor (coordinated disclosure)"},{"time":"2026-09-15T00:00:00.000Z","lang":"en","value":"Planned public disclosure (90-day window)"}],"credits":[{"lang":"en","value":"Arjun Basnet, Securin (arjun.basnet@securin.io)","type":"finder"}],"source":{"discovery":"EXTERNAL","advisory":"Securin Security Advisory — FINDING-004"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-01T13:10:10.152068Z","id":"CVE-2026-44041","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-01T13:10:40.100Z"}}]}}}