Security readout for executives and security teams
Plain-English summary
CVE-2020-16955 is a Microsoft Office Click-to-Run privilege escalation issue. A user would need to open a specially crafted file, after which the attacker could gain higher privileges on the affected system. This is high priority where vulnerable Office installations remain unpatched.
Executive priority
Treat as high priority for endpoint patching, especially in environments where Office files arrive through email or downloads. The vulnerability requires user action, but Office document handling is a common enterprise exposure path.
Technical view
Microsoft describes improper handling of certain files by Office Click-to-Run AppVLP components. The CVSS 3.1 score is 7.8 with local attack vector, low complexity, no attacker privileges required, and user interaction required. Successful exploitation can affect confidentiality, integrity, and availability.
Likely exposure
Exposure is most likely on endpoints running Microsoft Office 2013 Click-to-Run, Microsoft Office 2019, or Microsoft 365 Apps for Enterprise matching the affected entries and missing the relevant Microsoft security update.
Exploitation context
The source bundle does not show CISA KEV listing or cited active exploitation. The attack is user-assisted: Microsoft says an attacker must convince a user to open a specially crafted file. The CVSS vector indicates proof-of-concept exploit maturity, but not confirmed active abuse.
Researcher notes
Evidence is limited to CVE and Microsoft advisory data in the bundle. No CWE, exact fixed build list, or active exploitation source is provided. Validation should focus on Office Click-to-Run AppVLP exposure, installed product versions, update state, and user-assisted file-opening risk.
Mitigation direction
- Apply the Microsoft security update for CVE-2020-16955 to affected Office installations.
- Prioritize managed endpoints with affected Office Click-to-Run or Microsoft 365 Apps deployments.
- Check Microsoft guidance for exact fixed builds and update channels.
- Use endpoint controls to reduce delivery and opening of untrusted Office files.
Validation and detection
- Inventory Office versions and update channels across managed endpoints.
- Confirm affected products are updated per Microsoft guidance for CVE-2020-16955.
- Review endpoint telemetry for suspicious Office-launched child processes or privilege anomalies.
- Verify email and web controls restrict untrusted specially crafted files.
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.
Privilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2020-16955 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2020-16955CVE 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.