CVE-2021-29108Network attack vector

Account impersonation via SAML signature wrapping

Published Oct 1, 2021 · Updated Apr 10, 2025

Improper signature verification in Esri Portal for ArcGIS 10.9 and earlier allows remote authenticated users to impersonate accounts. The organization-specific SAML login path accepts a wrapped assertion whose signed element differs from the identity element it processes. Exploitation requires interception and modification of a legitimate SAML assertion, and the resulting session assumes the targeted account's access.

CVSS severity8.8
High
EPSS probability0.81%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper signature verification in Esri Portal for ArcGIS 10.9 and earlier allows remote authenticated users to impersonate accounts. The organization-specific SAML login path accepts a wrapped assertion whose signed element differs from the identity element it processes. Exploitation requires interception and modification of a legitimate SAML assertion, and the resulting session assumes the targeted account's access.

The record

CVE
CVE-2021-29108
Published
Oct 1, 2021
Updated
Apr 10, 2025
Vendor
Esri
Product
Portal for ArcGIS
Classifications
CWE-347, T1606.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 1, 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=10.9.0 <<10.9.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Esri · Portal for ArcGISversion=10.9.0 <<10.9.0

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
8.4EsriCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/RL:O/RC:C
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8EsriCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1606.002Forge Web Credentials: SAML Tokens

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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