Security readout for executives and security teams
Plain-English summary
CVE-2021-21045 is a high-severity Adobe Acrobat Reader DC installer access-control flaw. A local attacker could use it to gain elevated privileges in the context of the current user, increasing workstation compromise risk.
Executive priority
Treat as a high-priority endpoint patching issue. It is not described as internet-exploitable, but privilege escalation can turn a user-level foothold into broader business impact.
Technical view
Affected Acrobat Reader DC versions 2020.013.20074 and earlier, 2020.001.30018 and earlier, and 2017.011.30188 and earlier have improper access control. CVSS 3.1 is 8.2 with local access, low complexity, low privileges, and user interaction required.
Likely exposure
Exposure is mainly endpoints running affected Acrobat Reader DC versions, especially where users can launch installers or update workflows. Servers are unlikely unless Reader is installed interactively.
Exploitation context
The bundle does not show CISA KEV status or evidence of active exploitation. The CVSS vector indicates local exploitation requiring some user interaction, not a remote unauthenticated network attack.
Researcher notes
Evidence is limited to CVE metadata and Adobe’s advisory reference. Do not assume exploit availability, fixed build numbers, or mitigations beyond vendor guidance without consulting APSB21-09 directly.
Mitigation direction
- Inventory endpoints for affected Acrobat Reader DC versions.
- Review Adobe APSB21-09 for the vendor-approved update path.
- Prioritize updates on shared, kiosk, and high-privilege-user workstations.
- Restrict unnecessary local installer execution where operationally feasible.
- Monitor Adobe guidance for any revised remediation details.
Validation and detection
- Check installed Acrobat Reader DC versions against affected version thresholds.
- Confirm patched endpoints no longer report affected builds.
- Review software deployment logs for successful Adobe remediation.
- Validate high-risk workstation groups were included in patch scope.
- Check vulnerability scanner detections after remediation cycles complete.
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-284: Authorization and privilege behavior lookup
Authorization weaknesses can support privilege escalation and valid-account review, depending on exploit path. 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 lookupPrivilege 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-2021-21045 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
- 8.2 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/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:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H1.56Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.2HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://helpx.adobe.com/security/products/acrobat/apsb21-09.htmlCVE 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.
Improper Access Control
Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.