Security readout for executives and security teams
Plain-English summary
This is a low-severity Adobe Acrobat Reader DC issue that could leak limited sensitive memory data if a user opens a malicious file. It does not allow code execution, system takeover, or data modification based on the provided sources.
Executive priority
Treat this as routine patch hygiene, not an emergency. The business risk is mainly confidentiality exposure from malicious documents on unpatched user workstations, with no active exploitation evidence in the supplied sources.
Technical view
CVE-2021-28643 is a CWE-843 type confusion vulnerability associated with Adobe Acrobat Reader DC and embedDocAsDataObject. A local, unauthenticated attacker needs user interaction and may disclose memory information in the current user's context. CVSS is 3.3.
Likely exposure
Exposure is limited to endpoints running Acrobat Reader DC versions 2021.005.20054 and earlier, 2020.004.30005 and earlier, or 2017.011.30197 and earlier, especially where users open PDFs from untrusted sources.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires a malicious file and a victim opening it locally, so phishing or document-sharing paths are the plausible delivery context.
Researcher notes
Evidence is limited to the CVE record and Adobe advisory reference. The issue is confidentiality-only under CVSS, with local attack vector and required user interaction. Do not assume exploit availability or broader Acrobat product impact from these sources alone.
Mitigation direction
- Review Adobe APSB21-51 for vendor update guidance.
- Update affected Acrobat Reader DC installations beyond the listed vulnerable versions.
- Prioritize managed endpoints that handle external PDFs.
- Reinforce policy against opening unexpected PDF attachments.
- Use endpoint inventory to find obsolete Acrobat Reader tracks.
Validation and detection
- Confirm installed Acrobat Reader DC versions across managed endpoints.
- Check whether any endpoints remain on affected 2017, 2020, or 2021 builds.
- Verify Adobe APSB21-51 remediation is applied where relevant.
- Review email and web controls for unexpected PDF delivery risk.
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-843: Exact CWE lookup
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Open ATT&CK lookupCVE-2021-28643 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
- Low
- CVSS
- 3.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
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:L/I:N/A:N1.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
3.3LowVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://helpx.adobe.com/security/products/acrobat/apsb21-51.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.
Access of Resource Using Incompatible Type ('Type Confusion')
Access of Resource Using Incompatible Type ('Type Confusion') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.