UltraVNC Viewer 1.2.2.4 Denial of Service via Buffer Overflow
Published Mar 22, 2026
7.1
HIGHCVSS 4.0
EPSS 0.69%
Description
UltraVNC Viewer 1.2.2.4 contains a denial of service vulnerability that allows attackers to crash the application by supplying an oversized string to the VNC Server input field. Attackers can paste a malicious string containing 256 repeated characters into the VNC Server field and click Connect to trigger a buffer overflow that crashes the viewer.
Affected products
-
- Version 1.2.2.4StatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Uvnc | UltraVNC Viewer | n/a |
|
No data.
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
1 other source (NVD) ▾
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/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
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
PoCAutomatable
YesTechnical Impact
PartialDecision
n/aAssessed Mar 24, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 3, 2026.
Score over time
Mar–Oct 2026- EPSS v4
- EPSS v5
Percentile over time
- EPSS v4
- EPSS v5
Table of values (3 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 3, 2026 | 0.69% (0.00689) | 51.09th | v5 (v2026.06.15) |
| Jun 15, 2026 | 0.69% (0.00689) | 47.73th | v5 (v2026.06.15) |
| Mar 23, 2026 | 0.03% (0.00033) | 9.50th | v4 (v2025.03.14) |
References (4)
- https://www.exploit-db.com/exploits/46702 exploit
- https://www.uvnc.com/ product
- https://www.uvnc.com/downloads/ultravnc/126-download-ultravnc-1224.html product
- https://www.vulncheck.com/advisories/ultravnc-viewer-denial-of-service-via-buffer-overflow third-party-advisory
| Link | Providers | Tags |
|---|---|---|
| https://www.exploit-db.com/exploits/46702 | exploit | |
| https://www.uvnc.com/ | product | |
| https://www.uvnc.com/downloads/ultravnc/126-download-ultravnc-1224.html | product | |
| https://www.vulncheck.com/advisories/ultravnc-viewer-denial-of-service-via-buffer-overflow | third-party-advisory |
Change history (0)
No recorded changes yet.