Security readout for executives and security teams
Plain-English summary
This is a stored XSS issue in Esri Portal for ArcGIS. An attacker may store malicious strings in the home application, causing script execution when another user views affected content. Business impact is mainly account/session exposure, misleading content, and unauthorized actions in a user’s browser, not direct system takeover.
Executive priority
Treat as a moderate-priority remediation for internet-facing or broadly used Portal deployments. Prioritize faster if administrators or high-value users regularly access the home application, because stored XSS can compromise browser sessions and trust in the portal.
Technical view
CVE-2021-29110 is CWE-79 stored XSS in Portal for ArcGIS. The CVSS vector is network reachable, low complexity, low privileges, user interaction required, changed scope, and low confidentiality/integrity impact. The description says remote unauthenticated storage is possible, while the CVSS vector lists PR:L; this discrepancy is not resolved in the bundle.
Likely exposure
Exposure is likely limited to organizations running Esri Portal for ArcGIS, especially deployments where the home application is reachable by untrusted users. The bundle lists affected versions as “All,” but does not provide exact fixed-version boundaries or CPEs.
Exploitation context
The source bundle does not show CISA KEV listing or cited evidence of active exploitation. The issue requires a victim to view stored malicious content. Stored XSS can become more serious when privileged Portal users view attacker-controlled content.
Researcher notes
Evidence is sparse. The affected range is broad, and fixed-version detail is not included in the bundle. The unauthenticated description and PR:L CVSS field conflict, so validation should rely on Esri advisory details and local deployment behavior.
Mitigation direction
- Review Esri’s referenced Portal for ArcGIS Security 2021 Update 1 Patch guidance.
- Apply the relevant Esri security patch or supported upgrade path.
- Restrict public or untrusted access to Portal content creation where feasible.
- Monitor Esri advisories for exact affected and fixed version details.
Validation and detection
- Inventory all Portal for ArcGIS deployments and exposed home applications.
- Confirm installed patch level against Esri’s 2021 Update 1 Patch advisory.
- Review whether untrusted users can submit content rendered on the home application.
- Check logs and content changes for suspicious stored HTML or script-like strings.
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-2021-29110 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
- Medium
- CVSS
- 5.4 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N2.32.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.4MediumVector: CVSS:3.0/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.esri.com/arcgis-blog/products/arcgis-enterprise/administration/Portal-for-ArcGIS-Security-2021-Update-1-Patch/CVE reference · x_refsource_CONFIRM
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 Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.