CVE-2021-41791
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 · uneditedAn issue was discovered in Hyland org.alfresco:share through 7.0.0.2 and org.alfresco:community-share through 7.0. An evasion of the XSS filter for HTML input validation in the Alfresco Share User Interface leads to stored XSS that could be exploited by an attacker (given that he has privileges on the content collaboration features).
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 · moderate confidenceStored XSS vulnerability in Alfresco Share UI where the HTML input validation filter can be evaded, allowing authenticated users with content collaboration privileges to inject malicious scripts that execute when other users view the compromised content.
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<= 7.0>= 5.0.0.0, <= 5.2.7.11>= 6.0.1.0, <= 6.0.1.2>= 6.0.2.0, <= 6.2.2.4>= 6.1.1.0, <= 6.1.1.2= 7.0= 7.0.0.1= 7.0.0.2= 7.0.1CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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 Alfresco Share versionNavigate to the Share UI footer or check the alfresco-share.war file version manifest. Alternatively, check the tomcat/webapps/alfresco-share/WEB-INF/lib folder for share-community JAR files or the alfresco-version.properties file in the installation directory.Affected if The installed version matches one of the affected ranges: 5.0.0.0 to 5.2.7.11, 6.0.1.0 to 6.0.1.2, 6.0.2.0 to 6.2.2.4, 6.1.1.0 to 6.1.1.2, 7.0, 7.0.0.1, 7.0.0.2, 7.0.1, or Community Edition 7.0 and below.
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Verify HTML input validation filter configurationLocate the share-config-custom.xml or share-config.xml file in the tomcat/shared/classes/alfresco/web-extension directory. Inspect the HTML validation filter settings, specifically looking for input validation patterns that can be bypassed.Affected if The HTML input validation filter is configured and active without proper sanitization or allowlist-based filtering.
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Check user content collaboration privilegesIn the Alfresco Admin Console or Share UI user management section, identify users assigned the Content Collaborator role or equivalent permissions. Use the API endpoint /alfresco/service/api/people to enumerate users with collaborator-level access.Affected if Authenticated users with content collaboration or contributor privileges exist in the system.
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Inspect content metadata for injected scriptsAccess the Alfresco Share document library via the UI or use the REST API endpoint /alfresco/service/api/metadata?nodeRef=WORKSPACE://SpacesStore/ to inspect node properties. Check fields like description, title, and tags for unsanitized HTML or script tags.Affected if User-generated content fields contain unencoded HTML script tags, iframe elements, or event handler attributes (onclick, onerror, etc.).
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Review Content Security Policy headersUse browser developer tools or a command-line tool like curl to inspect HTTP response headers from the Share application. Look for CSP headers: curl -I https://your-server/share/page.Affected if Content Security Policy headers are missing or do not include unsafe-inline restrictions for script sources.
Your environment is affected if you run an affected Alfresco Share version AND have HTML input validation enabled with authenticated users holding content collaboration privileges, as the filter can be evaded to store malicious scripts.
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 · scopedImplement proper HTML sanitization and output encoding on all user input fields, update to patched version if available, and apply Content Security Policy headers to mitigate XSS execution.
Latest stable 7.x release (recommended: Community Share 7.0.1 or later, or Share 6.2.x/7.x)
- 1. Identify the exact current Alfresco Share or Community Share version deployed using the Alfresco admin console or about.xed endpoint
- 2. For Community Share: upgrade to version 7.0.1 or later (the next release after the affected 7.0.0.2)
- 3. For Alfresco Share (non-community): upgrade to a version higher than your current branch: 5.2.8 or later for 5.x line; 6.0.1.3 or later for 6.0.1.x line; 6.1.1.3 or later for 6.1.1.x line; 6.2.2.5 or later for 6.2.2.x line
- 4. After upgrade, verify the XSS filter properly sanitizes HTML input in content collaboration features
- 5. Test that stored XSS payloads are no longer executable in the Share UI
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-41791 — 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-2021-41791 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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