Security readout for executives and security teams
Plain-English summary
Adobe InDesign 16.0 and earlier can be compromised if a user opens a malicious crafted file. Successful exploitation could let an attacker run code with that user's privileges, putting documents and workstation data at risk.
Executive priority
Treat as a high-priority workstation remediation issue for creative, marketing, publishing, and design teams. The business risk depends on how often those users open files from outside trusted sources.
Technical view
CVE-2021-21099 is a high-severity CWE-787 out-of-bounds write in Adobe InDesign file parsing, identified in the source bundle as PCX parsing. The CVSS 3.1 score is 8.8, with no privileges required, user interaction required, and high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely on workstations running Adobe InDesign 16.0 or earlier, especially where users receive or open external design files. Server-side exposure is not indicated by the provided sources.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. Exploitation requires user interaction: the victim must open a malicious file. The impact is remote code execution in the current user's context.
Researcher notes
Evidence supports a memory-corruption RCE requiring file-open interaction. The bundle does not provide exploit details, observed exploitation, or specific fixed version data, so remediation should be anchored to Adobe's advisory.
Mitigation direction
- Review Adobe APSB21-22 and apply the vendor-recommended InDesign update.
- Prioritize systems running InDesign 16.0 or earlier.
- Limit opening unsolicited or untrusted design and image files.
- Use endpoint controls to reduce impact from user-context code execution.
Validation and detection
- Inventory endpoints for Adobe InDesign installations and versions.
- Flag InDesign 16.0 and earlier for remediation tracking.
- Confirm remediation status against Adobe APSB21-22 guidance.
- Check whether affected users handle external design 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-787: 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 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 lookupCVE-2021-21099 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/indesign/apsb21-22.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.
Out-of-bounds Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.