Security readout for executives and security teams
Plain-English summary
A malicious PDF could make affected Adobe Acrobat Reader versions run attacker-controlled code as the signed-in user. The victim must open the file, so email, downloads, and document-sharing workflows are the main concern. The source bundle does not show known active exploitation.
Executive priority
Treat as high priority for desktop patching, not an emergency zero-day based on provided evidence. The business risk is phishing-delivered code execution on user workstations, with severity depending on endpoint privileges and document intake volume.
Technical view
CVE-2021-28632 is a CWE-416 use-after-free in Acrobat Reader DC AcroForm field handling. Adobe reports arbitrary code execution in the current user context with CVSS 3.1 score 7.8. Affected versions include 2021.001.20155 and earlier, 2020.001.30025 and earlier, and 2017.011.30196 and earlier.
Likely exposure
Organizations are exposed where users can open PDFs in affected Adobe Acrobat Reader versions, especially endpoints receiving external documents by email, browser download, or collaboration platforms. Impact follows user privileges on the workstation.
Exploitation context
The vulnerability is unauthenticated but requires user interaction: a victim must open a malicious file. The provided sources do not identify public exploitation, weaponized samples, or CISA KEV listing for this CVE.
Researcher notes
The bundle identifies product family, affected version thresholds, CWE-416, CVSS vector, and user-interaction requirement. It does not provide root-cause details, proof-of-concept status, exploit maturity, or exact remediation version text beyond the Adobe bulletin reference.
Mitigation direction
- Update affected Acrobat Reader installations using Adobe APSB21-37 guidance.
- Prioritize endpoints handling external PDFs or high-risk email attachments.
- Reduce unsolicited PDF exposure through mail filtering and attachment sandboxing.
- Use least-privilege user accounts to limit post-exploitation impact.
Validation and detection
- Inventory Acrobat Reader versions across managed endpoints.
- Flag versions at or below the affected version numbers listed by Adobe/CVE.
- Confirm deployment of Adobe security updates referenced in APSB21-37.
- Review email and endpoint telemetry for suspicious PDF-driven process behavior.
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-416: 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-28632 mapping review
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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
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:H1.85.9Primary 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
Source materials
- CVE List V5 sourceCVE List V5
- https://helpx.adobe.com/security/products/acrobat/apsb21-37.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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.