Security readout for executives and security teams
Plain-English summary
This is a high-severity Adobe InCopy flaw where a malicious file can trigger code execution when opened. The attacker does not need an account, but they must convince a user to open the crafted file. Business risk is concentrated on endpoints using affected InCopy versions.
Executive priority
Treat as a targeted workstation risk, not a broad infrastructure emergency. Patch or remove affected InCopy installations promptly, especially for users who handle external documents, because successful exploitation can run code with the user's privileges.
Technical view
CVE-2021-21090 is a CWE-22 path traversal issue in Adobe InCopy file parsing. Sources state InCopy 16.0 and earlier are affected. Successful exploitation can lead to remote code execution as the current user, with high confidentiality, integrity, and availability impact under CVSS 3.1.
Likely exposure
Organizations are likely exposed only where Adobe InCopy 16.0 or earlier is installed and users can open untrusted crafted files. The provided source bundle does not include CPE detail or broader Adobe product impact.
Exploitation context
The bundle does not show CISA KEV listing or cited active exploitation. Exploitation requires user interaction: a victim must open a malicious file. Do not treat it as wormable or confirmed exploited from these sources alone.
Researcher notes
The available evidence identifies path traversal during crafted file parsing, but does not provide technical internals, exploit primitives, or patch mechanics. Validation should focus on product versioning, vendor advisory status, and exposure of users who open external documents.
Mitigation direction
- Review Adobe APSB21-25 and update InCopy according to vendor guidance.
- Prioritize affected creative, publishing, and document-handling workstations.
- Limit opening of unsolicited DOCX or project files from untrusted sources.
- Use email, web, and endpoint controls to quarantine suspicious document attachments.
- Remove or disable unused InCopy installations where business need is absent.
Validation and detection
- Inventory endpoints for Adobe InCopy installations and versions.
- Confirm whether any installations are version 16.0 or earlier.
- Verify remediation status against Adobe APSB21-25 guidance.
- Check endpoint controls for malicious attachment scanning coverage.
- Review user groups likely to receive external document files.
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-22: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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 lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. 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-2021-21090 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/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:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/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/incopy/apsb21-25.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.
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.