Security readout for executives and security teams
Plain-English summary
CVE-2021-21100 affects Adobe Digital Editions 4.5.11.187245 and earlier. A malicious file opened by a user could let an unauthenticated attacker write files as that user. This is not described as remotely self-spreading, but it can matter on workstations handling untrusted ebook or document content.
Executive priority
Treat this as a targeted endpoint risk, not an internet-facing emergency. Prioritize patching or removal where Adobe Digital Editions is present on user workstations that handle external files.
Technical view
The CVE describes a high-severity privilege escalation/arbitrary file system write issue in Adobe Digital Editions during installation. CVSS 3.1 is 7.8 with local attack vector, low complexity, no privileges required, and required user interaction. The weakness is mapped to CWE-379.
Likely exposure
Exposure is most likely on endpoints where Adobe Digital Editions 4.5.11.187245 or earlier is installed, especially users who open externally supplied files. Server exposure is not indicated by the provided sources.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires user interaction: a victim must open a malicious file. The provided CVSS vector marks attack vector as local.
Researcher notes
Evidence is limited to the CVE record and Adobe advisory reference in the bundle. Do not assume active exploitation or specific fixed versions unless confirmed from Adobe APSB21-26 or internal package data.
Mitigation direction
- Inventory Adobe Digital Editions installations and versions across managed endpoints.
- Review Adobe APSB21-26 and apply vendor-provided remediation guidance.
- Remove Adobe Digital Editions where there is no business need.
- Warn users not to open untrusted Digital Editions or ebook files.
- Use endpoint controls to limit execution and file writes from untrusted content.
Validation and detection
- Confirm whether Adobe Digital Editions is installed on endpoints.
- Flag versions 4.5.11.187245 and earlier as affected.
- Check software management records for remediation status against APSB21-26.
- Review endpoint detections for suspicious file writes by Digital Editions.
- Document any remaining business exceptions and compensating controls.
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-379: 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 lookupPrivilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-21100 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
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/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:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/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/Digital-Editions/apsb21-26.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.
Creation of Temporary File in Directory with Insecure Permissions
Creation of Temporary File in Directory with Insecure Permissions represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.