Security readout for executives and security teams
Plain-English summary
This is a low-severity Adobe Acrobat Reader information disclosure flaw. A user would need to open a malicious file or visit a malicious page. Successful exploitation could expose some sensitive information, but the provided sources do not indicate code execution, data modification, service outage, or active exploitation.
Executive priority
Treat as routine patch management unless the organization has heavy exposure to untrusted PDFs. The business risk is limited information disclosure, not confirmed active exploitation or system takeover.
Technical view
CVE-2021-40730 is a CWE-416 use-after-free in Acrobat Reader DC JPEG2000 image parsing. The CVSS 3.0 score is 3.3, with required user interaction and confidentiality impact only. Affected versions include the listed 21.x, 20.x, and 17.x Reader DC releases and earlier.
Likely exposure
Exposure is most likely on endpoints with Adobe Acrobat Reader DC versions at or below the affected releases, especially where users regularly open external PDFs or web-delivered documents.
Exploitation context
The bundle says exploitation requires user interaction through a malicious page or file. CISA KEV is false, and no cited source in the bundle supports active exploitation.
Researcher notes
Key evidence is limited to the CVE description, CVSS vector, CWE-416 classification, and Adobe advisory reference. The bundle does not provide exploit telemetry, exact fixed builds, or deeper root-cause detail.
Mitigation direction
- Apply Adobe security updates referenced by APSB21-104.
- Upgrade or remove Reader DC versions at or below the affected releases.
- Prioritize high-risk users who open external PDFs frequently.
- Maintain controls for untrusted attachments and downloaded documents.
- Check vendor guidance for exact fixed versions and deployment notes.
Validation and detection
- Inventory Adobe Acrobat Reader DC versions across endpoints.
- Compare installed versions against the affected release list.
- Confirm remediation status against Adobe APSB21-104 guidance.
- Validate coverage for shared, kiosk, and high-value workstations.
- Review helpdesk or EDR data for repeated malicious document exposure.
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 lookupCVE-2021-40730 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 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/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:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N1.81.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
3.3LowVector: CVSS:3.0/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/apsb21-104.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.