Security readout for executives and security teams
Plain-English summary
This is a low-severity Adobe Acrobat Reader issue that could let a malicious PDF read limited system information from the current user’s context. It is not a remote server compromise. The main business risk is targeted document delivery to users who still run affected Reader versions.
Executive priority
Handle through normal patch governance, with faster remediation for document-heavy teams. This does not warrant emergency response based on the provided evidence, but stale Acrobat Reader installs create avoidable exposure to malicious-file attacks.
Technical view
CVE-2021-35986 is a CWE-843 type confusion flaw associated with Acrobat Reader DC getAnnot handling. A local attack vector and required user interaction limit impact. Successful exploitation can disclose arbitrary system information with low confidentiality impact, without integrity or availability impact in the provided CVSS data.
Likely exposure
Organizations are exposed where Adobe Acrobat Reader DC versions 2021.005.20054 and earlier, 2020.004.30005 and earlier, or 2017.011.30197 and earlier remain installed and users can open untrusted PDF files.
Exploitation context
The provided sources say exploitation requires a victim to open a malicious file. CISA KEV status is false, and no provided source indicates active exploitation. Evidence does not support treating this as currently exploited in the wild.
Researcher notes
The public bundle supports limited confidentiality impact, local attack vector, no privileges required, and user interaction required. It does not include exploit details, fixed version identifiers, or evidence of active exploitation. Validate against Adobe APSB21-51 before closing remediation.
Mitigation direction
- Review Adobe APSB21-51 and apply vendor-recommended updates for affected Reader installations.
- Prioritize endpoints that receive external PDFs or handle sensitive business documents.
- Keep mail and web filtering controls active for suspicious document attachments.
- Retire unsupported Acrobat Reader deployment tracks where possible.
Validation and detection
- Inventory Acrobat Reader versions across managed endpoints.
- Flag versions at or below the affected thresholds listed in the CVE data.
- Confirm Adobe security updates from APSB21-51 are installed where applicable.
- Review endpoint telemetry for suspicious PDF open events if exposure existed.
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
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 lookupCVE-2021-35986 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
- https://www.zerodayinitiative.com/advisories/ZDI-21-1145/CVE 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.