Azure Core Shared Client LibraryApplication · Microsoft
CVE-2026-21226
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 · uneditedDeserialization of untrusted data in Azure Core shared client library for Python allows an authorized attacker to execute code over a network.
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 Azure Core shared client library for Python contains a deserialization vulnerability where untrusted data is processed without proper validation. This allows an authenticated attacker to send malicious serialized data that gets deserialized, leading to arbitrary code execution on the target system.
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
Azure Core Shared Client LibraryApplication
>= 1.1.0, < 1.38.0CVSS 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
- High
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/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.
-
Identify installed Azure Core library versionRun 'pip show azure-core' or check your requirements.txt/pipfile for the azure-core package versionAffected if The version displayed is >= 1.1.0 and < 1.38.0
-
Check for azure-core dependenciesRun 'pip list | grep azure' to see if azure-core or any azure-* packages that depend on it are installedAffected if Any azure-core related package in the 1.1.0 to 1.38.0 version range is present
-
Verify Python deserialization usageSearch code for pickle.loads, yaml.load with Loader=yaml.FullLoader, or similar deserialization of untrusted data that passes through azure-core client methodsAffected if The application deserializes data from untrusted network sources using azure-core client libraries
You are affected if azure-core version is >= 1.1.0 and < 1.38.0 AND your application deserializes data from untrusted sources through Azure Core client operations.
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 · scoped1.38.0
Update the Azure Core shared client library to the latest version that addresses this deserialization vulnerability. If no patch is available, implement input validation and restrict deserialization to only trusted, verified data sources.
azure-core>=1.38.0
- Run 'pip install --upgrade azure-core' to upgrade to the latest version
- Verify the installed version by running 'pip show azure-core'
- Confirm the installed version is >= 1.38.0
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Azure Core Shared Client Library
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,616.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-21226 — 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-2026-21226 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