Security readout for executives and security teams
Plain-English summary
This is a low-severity Adobe PDF parsing flaw. A user would need to open a malicious PDF, and the known impact is limited to possible sensitive information disclosure under that user's context. The provided sources do not show active exploitation or inclusion in CISA KEV.
Executive priority
Treat this as routine patch management, not an emergency. Prioritize endpoint update coverage for PDF-heavy teams, but current evidence supports low business urgency because exploitation needs user interaction and impact is limited to information disclosure.
Technical view
CVE-2021-21061 is a CWE-416 use-after-free in Adobe Acrobat/Reader PDF parsing. The CVSS 3.0 score is 3.3 with local attack vector, required user interaction, no privileges, and low confidentiality impact only. The bundle names Acrobat Pro DC versions at or below listed builds and also lists Acrobat Reader generically.
Likely exposure
Exposure is most likely on endpoints where users open PDFs with affected Adobe Acrobat Pro DC builds or the affected Adobe Reader entry listed in the source bundle. Internet-facing servers are not the primary exposure path based on the supplied vector.
Exploitation context
Exploitation requires convincing a user to open a specially crafted PDF. The source bundle states unauthenticated exploitation could disclose information in the current user's context. No supplied source supports active exploitation.
Researcher notes
The main caveat is product specificity: the description names Acrobat Pro DC build lines, while the affected entry lists Acrobat Reader with unspecified versions. Use Adobe APSB21-09 as the authoritative reconciliation point before scoping remediation.
Mitigation direction
- Check Adobe APSB21-09 for vendor-recommended updates and apply them to affected installations.
- Inventory Adobe Acrobat and Reader versions across endpoints.
- Reduce exposure to unsolicited PDFs through mail filtering and user awareness controls.
- Prioritize users handling external documents or sensitive files.
Validation and detection
- Compare installed Adobe versions against the affected build thresholds in the CVE description.
- Confirm endpoints are updated according to Adobe APSB21-09 guidance.
- Review email and endpoint telemetry for suspicious PDF delivery or opening events.
- Verify no CISA KEV listing is present in the supplied evidence.
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-2021-21061 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/apsb21-09.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.