Security readout for executives and security teams
Plain-English summary
CVE-2021-29105 is a stored cross-site scripting flaw in Esri ArcGIS Server Services Directory 10.8.1 and earlier. An authenticated remote user could store malicious text that later runs in another user's browser. Business risk is moderate because authentication and user interaction are required, but compromised sessions or data exposure are plausible.
Executive priority
Treat this as a scheduled security maintenance item unless exposed systems handle sensitive GIS data or broad authenticated user populations. Prioritize patching externally reachable or shared ArcGIS Server environments first.
Technical view
The CVE describes CWE-79 stored XSS in ArcGIS Server Services Directory. CVSS 3.0 is 5.4 with network access, low complexity, low privileges, required user interaction, changed scope, low confidentiality and integrity impact, and no availability impact. The provided evidence names version 10.8.1 and below.
Likely exposure
Organizations running Esri ArcGIS Server Services Directory version 10.8.1 or below are the likely exposure group. The bundle also lists ArcGIS Server versions as "All" without CPEs, so asset owners should verify exact affected versions against Esri guidance.
Exploitation context
The provided sources do not show known active exploitation, and KEV is false. Exploitation requires a remote authenticated attacker and a victim user viewing affected stored content. This is not described as unauthenticated remote code execution or a service availability issue.
Researcher notes
Evidence is concise and does not provide exploit telemetry, detailed vulnerable parameters, or full fixed-version mapping in the bundle. Avoid assuming exploit maturity. Focus validation on version, patch status, Services Directory reachability, authentication scope, and signs of stored unwanted content.
Mitigation direction
- Identify ArcGIS Server instances at version 10.8.1 or below.
- Apply Esri's ArcGIS Server Security 2021 Update 1 Patch where applicable.
- Review Esri guidance for supported-version upgrade or hardening instructions.
- Restrict Services Directory access to trusted authenticated users where business operations allow.
Validation and detection
- Confirm deployed ArcGIS Server versions and patch levels from asset inventory.
- Verify Services Directory exposure and authentication requirements for each instance.
- Review Services Directory content for unexpected stored script-like strings.
- Check vendor advisory status for CVE-2021-29105 coverage on installed builds.
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-2021-29105 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/arcgis-server-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.