Security readout for executives and security teams
Plain-English summary
Adobe Experience Manager had a stored cross-site scripting flaw in the Design Importer. A user with Author privileges could save script content into vulnerable fields. When another person opened the affected page, the script could run in their browser, creating risk to accounts, content integrity, and data handled in AEM.
Executive priority
Prioritize remediation for any production or externally reachable AEM authoring environment. The issue is critical because a low-privileged content author can create browser-side execution with potential confidentiality, integrity, and availability impact.
Technical view
CVE-2020-9740 is CWE-79 stored XSS affecting AEM 6.5.5.0 and below, 6.4.8.1 and below, 6.3.3.8 and below, and 6.2 SP1-CFP20 and below. CVSS 3.1 is 9.0: network reachable, low complexity, low privilege required, user interaction required, changed scope, and high CIA impact.
Likely exposure
Exposure is most likely where affected AEM versions are still deployed and Author users can access Design Importer fields. Internet-facing authoring environments, broad Author role assignment, and unreviewed imported design content increase practical business risk.
Exploitation context
The bundle does not cite active exploitation, and CISA KEV status is false. Exploitation requires an authenticated Author-level user and a victim opening content containing the stored script. Treat it as high-impact insider, compromised-author-account, or supply-chain content risk.
Researcher notes
Evidence is limited to CVE data and the Adobe advisory reference. The vulnerability is stored XSS in Design Importer fields, not an unauthenticated server compromise. Do not assume exploit availability, affected CPE precision, or fixed versions beyond Adobe guidance in APSB20-56.
Mitigation direction
- Review Adobe APSB20-56 and apply the vendor-provided AEM security update.
- Inventory AEM versions and prioritize systems at or below the listed affected releases.
- Restrict Author privileges to required users only.
- Review Design Importer content for unexpected script-bearing fields.
- Monitor AEM authoring activity for suspicious content changes.
Validation and detection
- Confirm each AEM instance version against the affected version list.
- Verify the Adobe APSB20-56 fix is installed where applicable.
- Identify users with Author privileges and validate business need.
- Review pages using Design Importer fields for suspicious stored script content.
- Check logs for recent edits to vulnerable content areas.
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 lookupCVE-2020-9740 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
- Critical
- CVSS
- 9 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/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:L/UI:R/S:C/C:H/I:H/A:H2.36Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9CriticalVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://helpx.adobe.com/security/products/experience-manager/apsb20-56.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.