CVE-2020-37133: ultravnc team ultravnc launcher Stack-based Buffer Overflow
Vulnerability summary
CVE-2020-37133 is a high (CVSS 7.5) Stack-based Buffer Overflow vulnerability in ultravnc team ultravnc launcher. EPSS estimates a 0.55% chance of exploitation in the next 30 days, higher than 44.6% of scored vulnerabilities. 1 public exploit is recorded.
Timeline
- 05-02-2026PublishedVulnerability first disclosed.
- 05-02-2026Last modifiedVulnerability information updated.
Description
UltraVNC Launcher 1.2.4.0 contains a denial of service vulnerability in the Repeater Host configuration field that allows attackers to crash the application. Attackers can paste an overly long string of 300 characters into the Repeater Host property to trigger an application crash.
CVSS metrics
4 scores · 2 sources · 2 versions- NVDNIST6.7MediumCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.55%
Chance of exploitation in the next 30 days
Percentile
45%
Versus all other CVEs
30-day change
+0.04 pp
From 0.50% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundUltraVNC Launcher 1.2.4.0 - 'RepeaterHost' Denial of Service (PoC)
Maturity: poc
Weaknesses
CWE · root cause- CWE-121Stack-based Buffer OverflowA stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
- CWE-787Out-of-bounds WriteThe product writes data past the end, or before the beginning, of the intended buffer.
Affected systems
Ultravnc team1 product
- ultravnc launcher1.2.4.0
Uvnc1 product
- ultravnc≤ 1.2.4.0
2 vendors · 2 products
References
3 links- www.uvnc.comProduct
- www.vulncheck.com/advisories/ultravnc-launcher-repeaterhost-denial-of-serviceThird Party Advisory