CVE-2026-0773
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 · uneditedUpsonic Cloudpickle Deserialization of Untrusted Data Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Upsonic. Authentication is not required to exploit this vulnerability. The specific flaw exists within the add_tool endpoint, which listens on TCP port 7541 by default. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the service account. Was ZDI-CAN-26845.
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 a critical deserialization vulnerability in Upsonic's Cloudpickle implementation. The add_tool endpoint (TCP port 7541) lacks proper validation of user-supplied data before deserialization, allowing attackers to send malicious pickle payloads that execute arbitrary code in the context of the service account without any authentication.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/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.
-
Verify if TCP port 7541 is open and listeningRun 'netstat -tuln | grep 7541' or 'ss -tuln | grep 7541' to check if the service is listening on port 7541Affected if Port 7541 is listening and accepting connections - this indicates the vulnerable endpoint may be exposed
-
Identify the service on port 7541Run 'nmap -sV -p 7541 <target_ip>' or 'curl -v http://<target_ip>:7541/' to identify what service is runningAffected if The service is Upsonic Cloudpickle or a related service - confirms the affected product is in use
-
Check Cloudpickle version in useIf Cloudpickle is installed, run 'pip show cloudpickle' or check the version in your Python environment dependenciesAffected if Cloudpickle version is present and matches the affected implementation - confirms the vulnerable library is in use
-
Determine if the add_tool endpoint is accessibleAttempt to reach the add_tool endpoint with a basic probe request (e.g., curl -X POST http://<target_ip>:7541/add_tool)Affected if The endpoint responds without requiring authentication - confirms the unauthenticated attack surface exists
-
Inspect service configuration for authentication settingsReview service configuration files or environment variables for authentication requirements on the add_tool endpointAffected if No authentication is enforced on the add_tool endpoint - confirms the full exploitation condition exists
You are affected if Cloudpickle is in use, port 7541 is exposed, the add_tool endpoint is accessible, and no authentication is required for that endpoint.
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 strict input validation and use safe deserialization methods (such as restricted unpickler classes) or replace cloudpickle with safer serialization formats. Consider network segmentation to limit exposure of port 7541.
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-0773 — 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-2026-0773 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