Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
The PyPI package azure-ai-language-conversations-authoring is vulnerable in versions before 1.0.0b4, due to deserialization of untrusted data in the Azure AI Language Conversations Authoring client library for Python. An unauthorized attacker with network access can exploit this to execute code. Upgrade to version 1.0.0b4 or later, which contains the fix.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 9.8 | Critical | 3.1 | 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 (microsoft) |
- CISA KEV Not listed.
- EPSS 0.025, the 85th percentile, on 12 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:07 UTC First seen by agentprime
- 31 Oct 2026, 14:07 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-436v-jg82-p533
- OSV: GHSA-436v-jg82-p533
- nvd.nist.gov/vuln/detail/CVE-2026-21531
- github.com/Azure/azure-sdk-for-python
- github.com/pypa/advisory-database/tree/main/vulns/azure-ai-language-conversations-authoring/PYSEC-2026-289.yaml
- msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21531
- pypi.org/project/azure-ai-language-conversations-authoring