CVE-2026-5026
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 · uneditedThe '/api/v1/files/images/{flow_id}/{file_name}' endpoint serves SVG files with the 'image/svg+xml' content type without sanitizing their content. Since SVG files can contain embedded JavaScript, an attacker can upload a malicious SVG that executes arbitrary JavaScript when viewed by other users, leading to stored cross-site scripting (XSS). This allows stealing authentication tokens stored in cookies, including JWT access and refresh tokens.
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 confidenceThe /api/v1/files/images/{flow_id}/{file_name} endpoint serves uploaded SVG files with the 'image/svg+xml' content type without sanitizing their content. Since SVG files can contain embedded JavaScript (event handlers, script tags, etc.), an attacker can upload a malicious SVG that executes arbitrary JavaScript in the browser of any user who views the file, leading to stored cross-site scripting (XSS). This enables attackers to steal authentication tokens including JWT access and refresh tokens stored in cookies.
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 dataall versionsCVSS 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.
-
Identify if Langflow is deployed in your environmentSearch for running processes containing 'langflow' or check for langflow installation directories, Docker containers, or service definitions. Look for the langflow web application serving on typical ports (7860, 8080).Affected if Langflow is installed and running in your environment
-
Confirm Langflow versionCheck the installed Langflow package version using 'pip show langflow' or inspect the container image/Dockerfile. If running from source, check the package __version__ or git tags.Affected if Any version of Langflow is running (all versions are affected)
-
Verify file upload functionality is enabledCheck Langflow configuration files (config.yaml, settings.py) or environment variables for upload-related settings. Look for directories where uploaded files are stored (often under /data, /uploads, or /tmp).Affected if File upload feature is enabled and the /api/v1/files/images/ endpoint is accessible
-
Check if SVG files can be uploadedAttempt to upload an SVG file through the Langflow interface or programmatically via the API endpoint. Inspect the uploaded file storage location to confirm SVG files are being saved.Affected if SVG files can be uploaded and stored in the system
-
Verify SVG files are served with unsafe content typeUpload an SVG file, then access it via the /api/v1/files/images/{flow_id}/{file_name} endpoint. Inspect the HTTP response headers using browser dev tools or curl -I to check if Content-Type is 'image/svg+xml'.Affected if Uploaded SVG files are served with 'Content-Type: image/svg+xml' without sanitization
You are affected if Langflow is running with file upload enabled and SVG files are served with the image/svg+xml content type, allowing embedded scripts to execute in user browsers.
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 dataImplement SVG sanitization to strip or disable embedded scripts, event handlers, and external resource references before serving files. Alternatively, serve SVG content with 'Content-Disposition: attachment' header or convert SVG to raster formats for display.
- Consultation2.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,248.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-5026 — 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-2026-5026 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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