Vendor
UltraVNC vulnerabilities
Updated . Rebuilt every hour.
Junglewise Threat Intelligence has tracked 10 vulnerabilities in UltraVNC: 0 in the last 7 days and 10 in the last 90 days, 2 of them critical and 0 exploited in the wild. The most recent, CVE-2026-7840, was published on 1 July 2026. 2 technologies have a page of their own.
- Last 7 days
- 0
- Last 90 days
- 10
- Critical, all time
- 2
- Exploited in the wild
- 0
About UltraVNC
UltraVNC is a developer of open-source remote administration and desktop sharing software for Microsoft Windows.
UltraVNC technologies
Latest UltraVNC vulnerabilities
- CVE-2026-7840: UltraVNC Repeater global buffer overflow in HTTP administration servercriticalCVSS 9.8
- CVE-2026-7839: UltraVNC Repeater hardcoded password in HTTP administration servercriticalCVSS 9.1
- CVE-2026-7838: UltraVNC viewer heap buffer overflow in RFB failure-response parsinghighCVSS 8.8
- CVE-2026-7831: UltraVNC Viewer off-by-one stack buffer overflow in RFB handlerhighCVSS 7.6
- CVE-2026-7830: UltraVNC weak cryptography in MS-Logon II authenticationhighCVSS 7.4
- CVE-2026-7829: UltraVNC Repeater out-of-bounds write in allow/deny rule parserhighCVSS 7.2
- CVE-2026-7828: UltraVNC Repeater integer overflow in HTTP request loggingmediumCVSS 5.3
- CVE-2026-44042: UltraVNC Repeater off-by-one error in HTTP Basic authenticationlowCVSS 3.7
- CVE-2026-44041: UltraVNC out-of-bounds read in vncWc2Mb conversion helpermediumCVSS 4.3
- CVE-2026-44040: UltraVNC weak PRNG in VNC authentication challengemediumCVSS 4.8
Most severe UltraVNC vulnerabilities
Exploited in the wild first, then by severity and CVSS score.
- CVE-2026-7840: UltraVNC Repeater global buffer overflow in HTTP administration servercriticalCVSS 9.8
- CVE-2026-7839: UltraVNC Repeater hardcoded password in HTTP administration servercriticalCVSS 9.1
- CVE-2026-7838: UltraVNC viewer heap buffer overflow in RFB failure-response parsinghighCVSS 8.8
- CVE-2026-7831: UltraVNC Viewer off-by-one stack buffer overflow in RFB handlerhighCVSS 7.6
- CVE-2026-7830: UltraVNC weak cryptography in MS-Logon II authenticationhighCVSS 7.4
- CVE-2026-7829: UltraVNC Repeater out-of-bounds write in allow/deny rule parserhighCVSS 7.2
- CVE-2026-7828: UltraVNC Repeater integer overflow in HTTP request loggingmediumCVSS 5.3
- CVE-2026-44040: UltraVNC weak PRNG in VNC authentication challengemediumCVSS 4.8
- CVE-2026-44041: UltraVNC out-of-bounds read in vncWc2Mb conversion helpermediumCVSS 4.3
- CVE-2026-44042: UltraVNC Repeater off-by-one error in HTTP Basic authenticationlowCVSS 3.7
Vulnerabilities per week
The last 13 weeks, by the week each vulnerability was published.
| Week of | Bar | Vulns | Critical |
|---|---|---|---|
| 29 Jun 2026 | 10 | 2 | |
| 6 Jul 2026 | 0 | 0 | |
| 13 Jul 2026 | 0 | 0 | |
| 20 Jul 2026 | 0 | 0 | |
| 27 Jul 2026 | 0 | 0 | |
| 3 Aug 2026 | 0 | 0 | |
| 10 Aug 2026 | 0 | 0 | |
| 17 Aug 2026 | 0 | 0 | |
| 24 Aug 2026 | 0 | 0 | |
| 31 Aug 2026 | 0 | 0 | |
| 7 Sep 2026 | 0 | 0 | |
| 14 Sep 2026 | 0 | 0 | |
| 21 Sep 2026 | 0 | 0 |
How this is built
Junglewise Threat Intelligence collects vulnerabilities from NVD, GitHub Security Advisories, OSV, the CISA Known Exploited Vulnerabilities catalog, FIRST EPSS and vendor advisories, and matches each one to the technologies and vendors it affects. Dates are the date a vulnerability was published, in UTC.
The pages are rebuilt from the database every hour. Frozen weekly and monthly reports never change once published, so they can be cited.
Use this data
The same data is at https://junglewise.ai/threats/vendors/ultravnc.json, for scripts and language models. It is free to reuse under CC BY 4.0 with a link back to this page.
Cite as: Junglewise Threat Intelligence, "UltraVNC vulnerabilities", https://junglewise.ai/threats/vendors/ultravnc, 26 September 2026.