Security readout for executives and security teams
Plain-English summary
CVE-2021-21084 is a stored cross-site scripting issue in Adobe Experience Manager. A logged-in attacker could place malicious script in vulnerable form fields, causing it to run when another user views the affected page. Business risk is highest where AEM is used for public web content, customer portals, or privileged author workflows.
Executive priority
Treat this as high priority for AEM environments with many content authors or sensitive authenticated users. The issue can enable browser-side compromise of trusted users, but provided sources do not show confirmed active exploitation.
Technical view
Adobe Experience Manager Cloud Service and AEM 6.5.7.0 and below, 6.4.8.3 and below, and 6.3.3.8 and below are described as affected. The CVSS 3.1 score is 7.3, with network access, low complexity, low privileges, and required user interaction. The impact is high confidentiality and integrity, with no availability impact stated.
Likely exposure
Exposure is likely limited to organizations running the affected AEM versions or AEM Cloud Service at the time covered by Adobe’s advisory. The attacker needs some privilege to submit vulnerable content, and a victim must browse the affected page.
Exploitation context
The source bundle does not show CISA KEV listing or other evidence of active exploitation. This should be treated as a credible stored XSS risk, not as confirmed in-the-wild exploitation based on the provided sources.
Researcher notes
The vulnerability is CWE-79 stored XSS in AEM’s resource resolver factory context. The title mentions arbitrary code execution, but the provided description supports malicious JavaScript executing in a victim browser, not server-side code execution. Avoid overstating impact beyond the cited CVSS vector and Adobe advisory.
Mitigation direction
- Inventory AEM Cloud Service and on-prem AEM versions.
- Check Adobe APSB21-15 for vendor-approved fixes and guidance.
- Prioritize remediation for AEM 6.5.7.0 and below.
- Prioritize remediation for AEM 6.4.8.3 and 6.3.3.8 and below.
- Review untrusted or low-privilege authored content pending remediation.
Validation and detection
- Confirm whether any AEM instance matches the affected version ranges.
- Review Adobe APSB21-15 against deployed AEM release levels.
- Check whether vulnerable form fields are reachable by low-privilege users.
- Look for unexpected script content in recently authored pages or forms.
- Verify remediation status through version and change records.
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-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. 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-2021-21084 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
- 7.3 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/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:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N2.15.2Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.3HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://helpx.adobe.com/security/products/experience-manager/apsb21-15.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.