CVE-2026-21531
Azure SDK for Python Remote Code Execution Vulnerability
Deserialization of untrusted data in Azure SDK allows an unauthorized attacker to execute code over a network.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Azure SDK for Python Remote Code Execution Vulnerability
Deserialization of untrusted data in Azure SDK allows an unauthorized attacker to execute code over a network.
- Record
CVE-2026-21531- CVSS 3.1
- 9.8 Critical
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 - Weakness
- CWE-502
- Updated
- 2026-11-02
EUVDEUVD-2026-7338
Deserialization of untrusted data in Azure SDK allows an unauthorized attacker to execute code over a network.
- Record
EUVD-2026-7338- CVSS 3.1
- 9.8 Critical
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-436v-jg82-p533
Azure AI Language Authoring Elevation of Privilege Vulnerability can Lead to RCE
Deserialization of untrusted data in the Azure AI Language Conversations Authoring client library for Python allows an unauthorized attacker to execute code over a network.
- Record
GHSA-436v-jg82-p533- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-502
- Updated
- 2026-11-02
NVD
Deserialization of untrusted data in Azure SDK allows an unauthorized attacker to execute code over a network.
- Record
CVE-2026-21531- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-502
- Updated
- 2026-11-02
OSVGHSA-436v-jg82-p533
Azure AI Language Authoring Elevation of Privilege Vulnerability can Lead to RCE
Deserialization of untrusted data in the Azure AI Language Conversations Authoring client library for Python allows an unauthorized attacker to execute code over a network.
- Record
GHSA-436v-jg82-p533- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-502
- Updated
- 2026-11-02
OSVPYSEC-2026-289
Azure AI Language Authoring Elevation of Privilege Vulnerability can Lead to RCE
Deserialization of untrusted data in the Azure AI Language Conversations Authoring client library for Python allows an unauthorized attacker to execute code over a network.
- Record
PYSEC-2026-289- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
azure-ai-language-conversations-authoringPyPI |
before 1.0.0b4 | 1.0.0b4 |
azure-ai-language-conversations-authoringPyPI |
before 1.0.0b4, plus listed versions 1.0.0b11.0.0b21.0.0b3 |
1.0.0b4 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | NetVanguard-cmd/CVE-2026-21531 | 2026-02-11 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-21531 is a critical vulnerability (CVSS 9.8) in Microsoft Azure Ai Language Authoring, published February 10, 2026. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 2.54%, the 85th percentile. Fixed in azure-ai-language-conversations-authoring 1.0.0b4.
References
msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21531
nvd.nist.gov/vuln/detail/CVE-2026-21531
github.com/pypa/advisory-database/tree/main/vulns/azure-ai-language-conversations-authoring/PYSEC-2026-289.yaml
pypi.org/project/azure-ai-language-conversations-authoring