CVE-2021-29108
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedThere is an privilege escalation vulnerability in organization-specific logins in Esri Portal for ArcGIS versions 10.9 and below that may allow a remote, authenticated attacker who is able to intercept and modify a SAML assertion to impersonate another account (XML Signature Wrapping Attack). In addition patching, Esri also strongly recommends as best practice for SAML assertions to be signed and encrypted.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThis is an XML Signature Wrapping attack vulnerability in Esri Portal for ArcGIS SAML authentication. A remote, authenticated attacker can intercept and modify SAML assertions to bypass signature validation and impersonate other user accounts, achieving privilege escalation within the organization.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 10.9CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify Esri Portal for ArcGIS installation versionAccess the Portal Administrator Directory (typically at https://servername:7443/arcgis/portal/admin) and navigate to System > Properties > Platform Info, or check the installed software via the Windows Services panel for 'ArcGIS Portal' service to locate the version numberAffected if The installed version is 10.9 or lower (any version <= 10.9)
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Confirm SAML-based authentication is configuredLog into the Portal Administrator Directory and navigate to Security > SAML Configuration to verify that SAML identity provider integration has been enabledAffected if SAML authentication is enabled - the vulnerability only affects environments using SAML for user authentication
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Inspect SAML assertion signature settingsIn the SAML Configuration page, examine whether SAML assertions are configured to require digital signatures. Verify if 'Sign SAML Response' and 'Sign SAML Assertion' options are enabled for the identity providerAffected if SAML assertions are not signed, or signature validation is optional/not enforced - this allows the XML Signature Wrapping attack to succeed
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Check for unauthorized access or privilege escalation indicatorsReview Portal audit logs and user sign-in logs for unusual authentication patterns, particularly SAML logins from users accessing resources or administrative functions outside their normal permissionsAffected if Evidence exists of users accessing resources or administrative functions they should not have permissions for, particularly following SAML-based logins
Your environment is affected if Esri Portal for ArcGIS is version 10.9 or lower AND SAML authentication is enabled AND SAML assertions are not properly signed/validated, allowing an authenticated attacker to potentially impersonate other users.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scopedApply the vendor patch for Esri Portal for ArcGIS to the fixed version (10.9.1 or higher). Additionally, ensure all SAML assertions are signed and encrypted as recommended by Esri to prevent assertion tampering.
Portal for ArcGIS version above 10.9 (contact Esri for specific patch version)
- 1. Review Esri's official security patches and product updates at https://www.esri.com/en-us/arcgis/security or the Esri Support website
- 2. Download and apply the latest Portal for ArcGIS patch that addresses CVE-2021-29108
- 3. As a best practice configuration change, ensure all SAML assertions are signed and encrypted in your IdP configuration
- 4. Verify the SAML authentication workflow after patching to confirm the vulnerability is remediated
- 5. Review other SAML-related security settings in Portal for ArcGIS administration
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-29108 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-29108 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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