CVE-2021-29103Network attack vector

User-assisted script execution via crafted link

Published Jul 11, 2021 · Updated Apr 10, 2025

Reflected XSS in Esri ArcGIS Server 10.8.1 and earlier allows remote attackers to execute JavaScript through a user-opened crafted link. Esri identifies the flaw only as reflected XSS and does not disclose the affected endpoint, parameter, or unsafe reflection operation. Successful exploitation requires a user to open the link and runs script under the ArcGIS Server browser origin, allowing limited access to content and actions available to that session.

CVSS severity6.1
Medium
EPSS probability0.74%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Esri ArcGIS Server 10.8.1 and earlier allows remote attackers to execute JavaScript through a user-opened crafted link. Esri identifies the flaw only as reflected XSS and does not disclose the affected endpoint, parameter, or unsafe reflection operation. Successful exploitation requires a user to open the link and runs script under the ArcGIS Server browser origin, allowing limited access to content and actions available to that session.

The record

CVE
CVE-2021-29103
Published
Jul 11, 2021
Updated
Apr 10, 2025
Vendor
Esri
Product
ArcGIS Server
Classifications
CWE-79, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 10, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=All <10.9

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Esri · ArcGIS Serverversion=All <10.9

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
5.8EsriCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/RL:O
6.1EsriCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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