Security readout for executives and security teams
Plain-English summary
CVE-2020-17395 affects Parallels Desktop 15.1.4. A local attacker who already has high-privileged code execution inside a guest VM could use a flaw to execute code in the hypervisor context. That makes it important for virtualization hosts, but the prerequisite access limits broad internet-style exposure.
Executive priority
Treat as high priority for virtualization endpoints running Parallels Desktop 15.1.4. The business risk is strongest where guest VM administrators are not fully trusted or guests may be compromised.
Technical view
The flaw is in the Parallels prl_naptd process. Inadequate validation of user-supplied data can cause an integer underflow before a memory write, enabling privilege escalation to hypervisor context. CVSS 3.0 is 7.5 with local attack vector, high complexity, and high privileges required.
Likely exposure
Exposure is most likely on systems running Parallels Desktop 15.1.4, especially where untrusted or compromised users can obtain privileged execution inside guest systems. The sources do not identify other affected versions or products.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires local conditions and high-privileged code execution in the guest before attempting escalation into the hypervisor context.
Researcher notes
This is ZDI-CAN-11134 and maps to CWE-191. The main research focus is host-guest boundary impact through prl_naptd, not remote network exposure. Evidence in the provided bundle is sufficient for affected product, prerequisite access, and impact, but incomplete on exact fixed versions.
Mitigation direction
- Inventory Parallels Desktop installations and identify version 15.1.4.
- Check Parallels guidance for the vendor-supported fix or workaround.
- Prioritize remediation on hosts running untrusted or shared guest VMs.
- Limit privileged guest access until affected hosts are remediated.
- Monitor vendor advisories for any expanded affected-version information.
Validation and detection
- Confirm installed Parallels Desktop versions across managed endpoints.
- Identify hosts where guest users can run privileged code.
- Review the Parallels KB and ZDI advisory for remediation status.
- Verify vulnerable hosts are updated or otherwise addressed per vendor guidance.
- Document exceptions where Parallels Desktop 15.1.4 remains installed.
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-191: 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-2020-17395 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 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/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:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H0.86Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
7.5HighVector: CVSS:3.0/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://kb.parallels.com/en/125013CVE reference · x_refsource_MISC
- https://www.zerodayinitiative.com/advisories/ZDI-20-1013/CVE reference · x_refsource_MISC
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.
Integer Underflow (Wrap or Wraparound)
Integer Underflow (Wrap or Wraparound) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.