Vulnerability · Published Feb 10, 2026 · Assigned by microsoft
CVE-2026-21531Azure SDK for Python Remote Code Execution Vulnerability
Critical 9.8
In plain English
A critical-severity unsafe deserialization in Azure AI Language Authoring from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 2.5% (higher than 85% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code. Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)9.8Critical
Exploit odds (30 days)2.5%top 14.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack tooling1Public PoC
Official description
Deserialization of untrusted data in Azure SDK allows an unauthorized attacker to execute code over a network.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | azure-ai-language-conversations-authoring | 1.0.0b4 | GHSA-436v-jg82-p533 |
| PyPI | azure-ai-language-conversations-authoring | 1.0.0b4 | PYSEC-2026-289 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Azure AI Language Authoring | 1.0.0 – before 1.0.0b4 |
Weakness: CWE-502 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Azure SDK for Python Remote Code Execution Vulnerability vendor-advisory, patch