{"id":"CVE-2026-7828","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-7828","generatedAt":"2026-10-28T02:12:44.745Z","title":"UltraVNC repeater through 1.8.2.2 contains an integer overflow in the HTTP request logging path.","description":"UltraVNC repeater through 1.8.2.2 contains an integer overflow in the HTTP request logging path. In repeater/webgui/settings.c:336, the win_log() function allocates list nodes via malloc(sizeof(struct LIST) + strlen(line)), where line is derived from HTTP request URIs. If strlen(line) is sufficiently large, the addition overflows to a value smaller than sizeof(struct LIST), causing a heap allocation smaller than required. The subsequent strcpy of the full string into the undersized allocation produces a heap buffer overflow. In the current implementation this overflow is bounded by the HTTP receive buffer size (WI_RXBUFSIZE = 153600 bytes, well below SIZE_MAX on 32-bit builds), limiting practical exploitability to a partial heap write. A remote unauthenticated attacker can trigger the theoretical overflow path by sending a maximally-sized URI in an HTTP request to the repeater HTTP port.","published":"2026-07-01T05:16:24.000Z","lastModified":"2026-10-25T17:10:00.000Z","status":"Modified","sourceIdentifier":"33c584b5-0579-4c06-b2a0-8d8329fcab9c","cvss":{"version":"3.1","score":5.3,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},"cwe":["CWE-190"],"affected":["uvnc/ultravnc"],"epss":{"score":0.01352,"percentile":0.71346,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (1.35%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://github.com/ultravnc/UltraVNC","tags":["Product"],"source":"33c584b5-0579-4c06-b2a0-8d8329fcab9c"},{"url":"https://uvnc.com/","tags":["Product","Release Notes"],"source":"33c584b5-0579-4c06-b2a0-8d8329fcab9c"},{"url":"https://www.securin.io/zero-days/cve-2026-7828-integer-overflow-win-log-malloc-ultravnc-repeater","source":"33c584b5-0579-4c06-b2a0-8d8329fcab9c"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-7828","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}