CVE-2026-5027
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 'POST /api/v2/files' endpoint does not sanitize the 'filename' parameter from the multipart form data, allowing an attacker to write files to arbitrary locations on the filesystem using path traversal sequences ('../').
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 confidenceThe POST /api/v2/files endpoint accepts multipart form data containing a 'filename' parameter that is used directly in constructing the file write path without sanitization. An attacker can embed path traversal sequences ('../') in the filename to write files outside the intended upload directory to arbitrary filesystem locations.
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< 1.9.0CVSS 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 the running service versionQuery the service's version endpoint, check process.argv, or inspect the deployed binary/package manifest to determine the exact version installedAffected if The installed version falls within any affected version range for CVE-2026-5027
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Confirm the /api/v2/files endpoint is exposedSend a GET or OPTIONS request to POST /api/v2/files to verify the endpoint exists and is accessibleAffected if The endpoint is reachable and accepts multipart form uploads
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Inspect the upload directory configurationExamine configuration files (e.g., config.json, settings.yaml, environment variables) for upload_path, upload_dir, or similar upload directory settingsAffected if No explicit upload directory restriction is configured or the path is not sanitized elsewhere
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Check for filename validation in application logsReview application logs for any path traversal sequences in upload attempts or for validation failures related to the filename parameterAffected if No filtering or rejection of '../' sequences is logged or enforced on the filename parameter
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Test if path traversal sequences are rejectedSend a test multipart upload request with a filename containing '../' sequences and observe the response behaviorAffected if The application accepts the path traversal sequences without rejecting or sanitizing them
You are affected if the service runs a version within the affected range, the /api/v2/files endpoint is exposed, and the filename parameter accepts path traversal sequences without validation.
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 data1.9.0
Implement strict input validation on the filename parameter to reject or strip path traversal sequences ('../'), and use randomized internal filenames with a controlled upload directory to prevent arbitrary file writes.
- Consultation3.0 h
- Implementation6.0 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 $4,992.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-5027 — 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-2026-5027 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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