Security readout for executives and security teams
Plain-English summary
This is a high-severity Adobe Acrobat Reader flaw. If a user opens a malicious file, the attacker could run code with that user's privileges. The main business risk is compromise of endpoints through document-based phishing or file delivery.
Executive priority
Treat this as a priority endpoint patching issue, especially for staff exposed to external documents. It is not confirmed as actively exploited in the provided sources, but arbitrary code execution through user-opened files is a credible business risk.
Technical view
CVE-2021-28564 is a CWE-787 out-of-bounds write in Acrobat Reader's ImageTool component. A remote unauthenticated attacker can achieve arbitrary code execution in the current user context, but exploitation requires user interaction: the victim must open a malicious file.
Likely exposure
Exposure is likely on endpoints running Acrobat Reader DC 2021.001.20150 or earlier, 2020.001.30020 or earlier, or 2017.011.30194 or earlier. Systems where users routinely open external PDFs have higher practical risk.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. The documented attack path requires convincing a user to open a malicious file, so phishing and file-sharing workflows are the realistic exposure context.
Researcher notes
The record identifies ImageTool as the affected component and CWE-787 as the weakness class. The provided affected-version data is limited to release thresholds, and no exploit details or independent exploitation confirmation are included.
Mitigation direction
- Review Adobe APSB21-29 for the vendor-approved update path.
- Update affected Acrobat Reader installations according to Adobe guidance.
- Prioritize users who handle external documents or email attachments.
- Restrict untrusted document handling where patching is delayed.
- Use endpoint controls to limit code execution from document workflows.
Validation and detection
- Inventory Acrobat Reader versions across managed endpoints.
- Compare versions against the affected release thresholds.
- Confirm patched systems no longer report affected Acrobat Reader builds.
- Review exposure for users who receive external PDFs.
- Check security telemetry for suspicious document-delivery activity.
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-787: 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-2021-28564 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/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:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/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/apsb21-29.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.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.