Security readout for executives and security teams
Plain-English summary
CVE-2020-37134 is a denial-of-service issue in UltraVNC Viewer 1.2.4.0. Malformed VNC server input can crash the viewer application. This affects availability of the remote-access client, not confidentiality or data integrity based on provided sources.
Executive priority
Treat as a focused availability risk. Prioritize if UltraVNC Viewer 1.2.4.0 is used in operational support or incident response workflows. It is less urgent than vulnerabilities enabling system compromise, but public exploit availability increases remediation importance.
Technical view
The issue is reported as CWE-770 in UltraVNC Viewer 1.2.4.0. The supplied CVSS is 7.5 High, with availability impact only. Public references include an ExploitDB entry and VulnCheck advisory. Source details conflict on user interaction: the description mentions pasting input into a connection dialog, while the CVSS vector says UI:N.
Likely exposure
Organizations are likely exposed only where UltraVNC Viewer 1.2.4.0 is installed or distributed to users. Exposure is most relevant for helpdesk, IT administration, and remote-support workflows using this specific viewer version.
Exploitation context
A public ExploitDB entry exists, so proof-of-concept knowledge is public. The source bundle does not show CISA KEV listing or confirmed active exploitation. The demonstrated impact is application crash rather than code execution or data theft.
Researcher notes
Evidence supports a client-side denial-of-service in a specific UltraVNC Viewer version. Do not assume server compromise, privilege escalation, or data exposure from the provided sources. The UI requirement ambiguity should be validated against the original advisory and CVE record before scoring changes.
Mitigation direction
- Inventory endpoints for UltraVNC Viewer 1.2.4.0.
- Check UltraVNC vendor guidance for fixed versions or recommended upgrades.
- Prioritize replacement or upgrade where the viewer supports critical operations.
- Restrict use of untrusted VNC server connection details where practical.
Validation and detection
- Confirm installed UltraVNC Viewer versions on managed endpoints.
- Review software deployment records for UltraVNC Viewer 1.2.4.0.
- Check vulnerability scanner results against CVE-2020-37134.
- Verify remediation by confirming the affected version is no longer present.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-770: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-37134 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- ExploitDB-48291CVE reference · exploit
- UltraVNC Official HomepageCVE reference · product
- VulnCheck Advisory: UltraVNC Viewer 1.2.4.0 - 'VNCServer' Denial of ServiceCVE reference · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Allocation of Resources Without Limits or Throttling
Allocation of Resources Without Limits or Throttling represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.