CVE-2026-21531 json
Azure SDK for Python Remote Code Execution Vulnerability
published 2026-02-10 8 mo ago modified 2026-10-27 13 d ago also GHSA-436v-jg82-p533 , PYSEC-2026-289 , EUVD-2026-7338
- cvss
- 9.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 2.5%
- EPSS 2.5% chance of exploitation in 30 days, percentile 85%
- public exploits
- 0
- none known
Summary
Deserialization of untrusted data in Azure SDK allows an unauthorized attacker to execute code over a network.
Patch / fix
- pypi azure-ai-language-conversations-authoring 1.0.0b4
- Microsoft Azure AI Language Authoring 1.0.0b4
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- total
- Assessed
- 8 mo ago
Exploit prediction
2.54% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 9.8 | 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 |
| CNA | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| GitHub | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
| OSV | 3.1 | 9.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| pypi | azure-ai-language-conversations-authoring | <1.0.0b4 |
1.0.0b4 |
Affected products
- Microsoft Azure AI Language Authoring
Classification
- Weakness
-
- CWE-502 Deserialization of Untrusted Data
References
-
msrc.microsoft.com
/update-guide/vulnerability/CVE-2026-21531
vendor-advisory, patch, web
-
nvd.nist.gov
/vuln/detail/CVE-2026-21531
advisory
-
github.com
/Azure/azure-sdk-for-python
package
-
github.com
/pypa/advisory-database/tree/main/vulns/azure-ai-language-conversations-authoring/PYSEC-2026-289.yaml
web
-
pypi.org
/project/azure-ai-language-conversations-authoring
web, package
-
github.com
/advisories/GHSA-436v-jg82-p533
advisory
Sources
- CVE List CVE-2026-21531
- GitHub Advisory GHSA-436v-jg82-p533
- NVD CVE-2026-21531
- OSV PYSEC-2026-289
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.