{"id":"CVE-2026-21531","kind":"vulnerability","aliases":["CVE-2026-21531","GHSA-436v-jg82-p533"],"related":[],"title":"Azure AI Language Authoring Elevation of Privilege Vulnerability can Lead to RCE","description":"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.","summary":"The Azure AI Language Conversations Authoring client library for Python deserializes untrusted data without checks. An unauthorized attacker can send crafted input over the network and execute code.","severity":"critical","cvss":9.8,"epss":0.0258,"exploited":false,"exploited_at":null,"products":[{"name":"azure-ai-language-conversations-authoring","fixed":["1.0.0b4"],"affected":"< 1.0.0b4","ecosystem":"pypi"},{"name":"microsoft azure conversation authoring client library","fixed":[],"affected":"= 1.0.0","ecosystem":"vendor"}],"ecosystems":["pypi","vendor"],"tags":["ai-language","azure","cwe-502","package","pypi","python"],"not_affected_if":["package-not-installed"],"how_to_check":"- Run `pip show azure-ai-language-conversations-authoring` and confirm the installed version is below `1.0.0b4`\n- Search lock files and requirements for `azure-ai-language-conversations-authoring` to find pinned versions","fix":"- Upgrade `azure-ai-language-conversations-authoring` to `1.0.0b4` or later\n- Rebuild and redeploy services that bundle this package","status":"open","published_at":"2026-02-10T18:16:35+00:00","first_seen_at":"2026-10-27T15:23:43+00:00","triaged_at":"2026-10-27T15:25:14+00:00","updated_at":"2026-10-27T15:32:59+00:00","category":"package","confidence":0.7,"triage":{"at":"2026-10-27T15:25:14Z","model":"claude-haiku-5-5","output":{"fix":"- Upgrade `azure-ai-language-conversations-authoring` to `1.0.0b4` or later\n- Rebuild and redeploy services that bundle this package","reach":"network","title":"Azure AI Language Authoring Python library: untrusted data runs code over network","impact":"high","summary":"The Azure AI Language Conversations Authoring client library for Python deserializes untrusted data without checks. An unauthorized attacker can send crafted input over the network and execute code.","category":"package","nicknames":[],"who_cares":["python","azure","ai-language","pypi"],"confidence":0.7,"needs_auth":"unknown","worst_case":"Attacker executes code on the server running the client","analyst_note":"Sources do not say which API calls or payload types reach the unsafe deserialization path; check the GHSA-436v-jg82-p533 advisory for affected methods.","how_to_check":"- Run `pip show azure-ai-language-conversations-authoring` and confirm the installed version is below `1.0.0b4`\n- Search lock files and requirements for `azure-ai-language-conversations-authoring` to find pinned versions","needs_analyst":true,"not_affected_if":["package-not-installed"],"who_is_affected":"Any application that imports the Azure AI Language Conversations Authoring Python client and sends it data that can come from outside the trust boundary is exposed. Teams that do not install this package, or that only call the service with fixed, trusted inputs, can skip it, though the upgrade is still cheap.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"critical"},"cost_usd":0.00061,"input_tokens":3331,"output_tokens":553,"severity_before":"critical"},"analyst_status":null,"analyst_note":null,"search":"'-2026':14A,22A '-21531':15A,23A '-502':41B '436v':18A 'ai':2A,26A,37B,47B,80C 'ai-languag':36B 'allow':88C 'attack':62B,91C 'author':4A,50B,83C 'authoring':29A,33A 'azur':1A,39B,46B,79C 'azure':25A,31A 'azure-ai-language-conversations-authoring':24A 'check':59B 'client':34A,51B,84C 'code':72B,94C 'convers':49B,82C 'conversation':32A 'conversations':28A 'craft':65B 'cve':13A,21A 'cwe':40B 'data':57B,76C 'deseri':55B,73C 'elev':5A 'execut':71B,93C 'ghsa':17A 'ghsa-436v-jg82-p533':16A 'input':66B 'jg82':19A 'languag':3A,38B,48B,81C 'language':27A 'lead':10A 'librari':52B,85C 'library':35A 'microsoft':30A 'network':69B,97C 'p533':20A 'packag':42B 'privileg':7A 'pypi':43B 'python':44B,54B,87C 'rce':12A 'send':64B 'unauthor':61B,90C 'untrust':56B,75C 'vulner':8A 'without':58B","nicknames":[],"mitigations":[],"who_affected":"Any application that imports the Azure AI Language Conversations Authoring Python client and sends it data that can come from outside the trust boundary is exposed. Teams that do not install this package, or that only call the service with fixed, trusted inputs, can skip it, though the upgrade is still cheap.","tier":"B","verified":{},"analyst_revisit_at":null,"first_public_at":"2026-02-10T18:16:35+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvss_by":"GitHub","poc_count":0,"sources":[{"source":"ghsa","external_id":"GHSA-436v-jg82-p533","url":"https://github.com/advisories/GHSA-436v-jg82-p533","severity":"critical","published_at":"2026-02-10T18:30:42+00:00","modified_at":"2026-10-27T15:21:49+00:00","first_seen_at":"2026-10-27T15:23:43+00:00","fetched_at":"2026-10-27T15:23:43+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-21531","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-21531","severity":null,"published_at":"2026-02-10T18:16:35+00:00","modified_at":"2026-06-17T10:18:47+00:00","first_seen_at":"2026-10-27T15:32:59+00:00","fetched_at":"2026-10-27T15:32:59+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}