{"id":"CVE-2026-107614","state":"PUBLISHED","title":"Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read","description":"An integer underflow in WinCursorShapeUtils::trimTransparent() in GlavSoft TightVNC Server for Windows before 2.8.88 allows a local authenticated user to crash the server, and potentially read out-of-bounds memory, by causing a cursor shape with a width or height of zero to be processed on the DXGI capture path. The loop bound width - 1 wraps to 0xFFFFFFFF, producing an access roughly 4 GB beyond the 64 KB cursor buffer; a monochrome cursor of height 1 also becomes 0 because getCursorHeight() halves the height in place.","publishedAt":"2026-10-08T13:39:58.297Z","updatedAt":"2026-10-08T14:01:01.624Z","severity":{"score":6.1,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H","source":"securin"},"assigner":"securin","products":["GlavSoft TightVNC"],"affected":[{"vendor":"GlavSoft","product":"TightVNC","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.8.88","versionType":"custom"}],"platforms":["Windows"],"modules":["TightVNC Server (cursor shape processing)"],"programFiles":["WinCursorShapeUtils.cpp"],"programRoutines":[{"name":"WinCursorShapeUtils::trimTransparent()"},{"name":"getCursorHeight()"}]}],"references":["https://sourceforge.net/p/vnc-tight/bugs/1661/","https://www.tightvnc.com/whatsnew.php"],"weaknesses":["CWE-191","CWE-125"],"ingestedAt":"2026-10-29T20:10:23.711Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/107xxx/CVE-2026-107614.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-107614","state":"PUBLISHED","datePublished":"2026-10-08T13:39:58.297Z","dateUpdated":"2026-10-08T14:01:01.624Z","assignerShortName":"securin","assignerOrgId":"33c584b5-0579-4c06-b2a0-8d8329fcab9c","dateReserved":"2026-10-08T13:23:07.677Z"},"containers":{"cna":{"title":"Integer underflow in TightVNC Server cursor shape trimming leads to out-of-bounds read","descriptions":[{"lang":"en","value":"An integer underflow in WinCursorShapeUtils::trimTransparent() in GlavSoft TightVNC Server for Windows before 2.8.88 allows a local authenticated user to crash the server, and potentially read out-of-bounds memory, by causing a cursor shape with a width or height of zero to be processed on the DXGI capture path. The loop bound width - 1 wraps to 0xFFFFFFFF, producing an access roughly 4 GB beyond the 64 KB cursor buffer; a monochrome cursor of height 1 also becomes 0 because getCursorHeight() halves the height in place."}],"affected":[{"vendor":"GlavSoft","product":"TightVNC","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"2.8.88","versionType":"custom"}],"platforms":["Windows"],"modules":["TightVNC Server (cursor shape processing)"],"programFiles":["WinCursorShapeUtils.cpp"],"programRoutines":[{"name":"WinCursorShapeUtils::trimTransparent()"},{"name":"getCursorHeight()"}]}],"references":[{"url":"https://sourceforge.net/p/vnc-tight/bugs/1661/","name":"TightVNC bug #1661","tags":["issue-tracking"]},{"url":"https://www.tightvnc.com/whatsnew.php","name":"TightVNC release notes (2.8.88)","tags":["release-notes","patch"]}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H","baseScore":6.1,"baseSeverity":"MEDIUM"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-191","lang":"en","type":"CWE","description":"CWE-191 Integer Underflow (Wrap or Wraparound)"}]},{"descriptions":[{"cweId":"CWE-125","lang":"en","type":"CWE","description":"CWE-125 Out-of-bounds Read"}]}],"providerMetadata":{"shortName":"securin","orgId":"33c584b5-0579-4c06-b2a0-8d8329fcab9c","dateUpdated":"2026-10-08T13:39:58.297Z"},"solutions":[{"lang":"en","value":"Upgrade TightVNC for Windows to version 2.8.88 or later."}],"credits":[{"lang":"en","type":"finder","value":"Arjun Basnet from Securin"}],"timeline":[{"time":"2026-05-30T00:00:00.000Z","lang":"en","value":"Reported to GlavSoft"},{"time":"2026-06-02T00:00:00.000Z","lang":"en","value":"Vendor acknowledged"},{"time":"2026-06-19T00:00:00.000Z","lang":"en","value":"TightVNC 2.8.88 released with fix"}],"source":{"discovery":"EXTERNAL"},"impacts":[{"capecId":"CAPEC-540","descriptions":[{"lang":"en","value":"CAPEC-540 Overread Buffers"}]}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-10-08T14:00:49.369592Z","id":"CVE-2026-107614","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":"2026-10-08T14:01:01.624Z"}}]}}}