Vendor
UltraVNC vulnerabilities
Updated . Rebuilt every hour.
Junglewise Threat Intelligence has tracked 11 vulnerabilities in UltraVNC: 1 in the last 7 days and 1 in the last 90 days, 2 of them critical and 0 exploited in the wild. The most recent, CVE-2026-128321, was published on 13 November 2026. Nothing was published in the last eight weeks. 2 technologies have a page of their own.
- Last 7 days
- 1
- Last 90 days
- 1
- 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-2026-128321: TightVNC and UltraVNC heap-based buffer overflow in Tight JPEG decodinginfo
- 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
Nothing was published in the last eight weeks. The last 13 weeks, by the week each vulnerability was published.
| Week of | Bar | Vulns | Critical |
|---|---|---|---|
| 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 | |
| 28 Sep 2026 | 0 | 0 | |
| 5 Oct 2026 | 0 | 0 | |
| 12 Oct 2026 | 0 | 0 | |
| 19 Oct 2026 | 0 | 0 | |
| 26 Oct 2026 | 0 | 0 | |
| 2 Nov 2026 | 0 | 0 | |
| 9 Nov 2026 | 1 | 0 |
Embed a badge
A live badge for a README, a status page or an internal wiki: how many UltraVNC vulnerabilities were published in the last 7 days and how many of them are critical, refreshed hourly.
[](https://junglewise.ai/threats/vendors/ultravnc)<a href="https://junglewise.ai/threats/vendors/ultravnc"><img src="https://junglewise.ai/threats/vendors/ultravnc/badge.svg" alt="UltraVNC vulnerabilities" /></a>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, and this page as text at https://junglewise.ai/threats/vendors/ultravnc.md, 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, 13 November 2026.