PatchSiren cyber security CVE debrief
CVE-2026-59867 microsoft CVE debrief
CVE-2026-59867 is a vulnerability in Kiota, an OpenAPI-based HTTP Client code generator. Prior to version 1.32.5, Kiota resolved OpenAPI $ref values by fetching remote http(s) URLs and reading local absolute or out-of-tree file paths. This allowed `kiota generate` on an attacker-controlled or attacker-influenced description to perform build-time SSRF, remote file inclusion, and local file inclusion by inlining external schemas such as REMOTE_KIOTA_PROP or Leaked into generated clients. The issue is fixed in version 1.32.5 by introducing the AllowedExternalOriginsStreamLoader and the --allowed-external-origins option. Developers and users of Kiota OpenAPI-based HTTP Client code generator, especially those using versions prior to 1.32.5, should be aware of this vulnerability and take necessary actions to mitigate the risk.
- Vendor
- microsoft
- Product
- kiota
- CVSS
- HIGH 7.1
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-07-16
- Original CVE updated
- 2026-07-16
- Advisory published
- 2026-07-16
- Advisory updated
- 2026-07-16
Who should care
Developers and users of Kiota OpenAPI-based HTTP Client code generator, especially those using versions prior to 1.32.5, should be aware of this vulnerability and take necessary actions to mitigate the risk. This includes operators, platform administrators, vulnerability management teams, and security teams who may be impacted by the vulnerability.
Technical summary
The vulnerability in Kiota allows for build-time SSRF, remote file inclusion, and local file inclusion due to the way OpenAPI $ref values are resolved. An attacker could exploit this by providing a malicious OpenAPI description, potentially leading to security breaches in generated clients. The issue arises from Kiota's ability to fetch remote http(s) URLs and read local absolute or out-of-tree file paths prior to version 1.32.5. This vulnerability can be mitigated by upgrading to version 1.32.5 or later and using the --allowed-external-origins option when generating clients.
Defensive priority
High
Recommended defensive actions
- Upgrade Kiota to version 1.32.5 or later
- Use the --allowed-external-origins option when generating clients
- Validate and sanitize OpenAPI descriptions before using them with Kiota
- Monitor generated clients for suspicious activity
- Review compensating controls for exposed systems while remediation is scheduled and verified
- Check relevant monitoring, detection, and logs for exposed assets that need extra review
- Track exceptions, retest remediated assets, and close the item only after evidence is documented
Evidence notes
The CVE record was published on 2026-07-16T16:19:15.620Z and has not been modified since then. The NVD entry is currently Deferred. There is no additional information available about the vulnerability beyond what is provided in the CVE record and NVD entry. However, it is essential to verify the affected scope, severity, and vendor guidance. The CVE record and NVD entry provide limited information, and defenders should be cautious when assessing the vulnerability.
Official resources
AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-16T16:19:15.620Z and has not been modified since then. The NVD entry is currently Deferred.