CVE-2021-27601
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 · uneditedSAP NetWeaver AS Java (Applications based on HTMLB for Java) allows a basic-level authorized attacker to store a malicious file on the server. When a victim tries to open this file, it results in a Cross-Site Scripting (XSS) vulnerability and the attacker can read and modify data. However, the attacker does not have control over kind or degree.
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 confidenceStored XSS vulnerability in SAP NetWeaver AS Java (HTMLB for Java applications). An authenticated attacker can upload a malicious file to the server; when other users access this file, the embedded XSS payload executes in their browser context, allowing the attacker to read and modify data within the victim's session.
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= 7.10= 7.11= 7.30= 7.31= 7.40= 7.50CVSS 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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Confirm SAP NetWeaver AS Java installationCheck for running SAP Java processes or examine installed software inventory on the server. Look for sapjvm processes or NetWeaver installation directories.Affected if SAP NetWeaver Application Server Java is installed and running
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Verify the NetWeaver Java versionAccess the SAP NetWeaver Administrator (NWA) console or check version files in the installation directory. Common paths include /usr/sap/<SID>/<instance>/j2ee or similar. Execute: sapcontrol -nr <instance> -function GetVersionInfo or check version.txt in the installation.Affected if The installed version is exactly 7.10, 7.11, 7.30, 7.31, 7.40, or 7.50
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Identify if HTMLB component is deployedCheck the SAP NetWeaver Administrator for deployed web applications. Look for HTMLB (HTMLB library) in the application list under Visual Administrator or via NWA: http://<host>:<port>/nwa. Navigate to Configuration -> Applications -> Enterprise Applications.Affected if HTMLB for Java applications is deployed and active on the system
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Determine if file upload functionality existsReview deployed web applications that allow file uploads. Check for upload servlets or file handling endpoints in the SAP NetWeaver Java web container. Look for upload-related JSP files or servlets in the /webdynpro/ or /irj/ directories.Affected if Any user-accessible file upload feature exists in the deployed Java applications
The environment is affected if SAP NetWeaver AS Java versions 7.10, 7.11, 7.30, 7.31, 7.40, or 7.50 are running with HTMLB component deployed and user-accessible file upload functionality enabled.
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.
From vendor dataApply SAP security patches for CVE-2021-27601. Additionally, implement strict input validation on file uploads and output encoding when serving files to prevent XSS execution.
- Consultation6.0 h
- Implementation12.0 h
- Testing10.0 h
- Review / QA6.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $9,504.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-27601 — 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-2021-27601 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data