CVE-2026-59866Kiota: Arbitrary file write + code-injection via x-ms-kiota-info clientClassName and clientNamespaceName
- 9.3CriticalCVSS base score
- 1.4%Exploitation in 30 daysEPSS · top 27% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.5, Kiota emitted x-ms-kiota-info clientClassName and clientNamespaceName values without identifier or path sanitization as both generated client class or namespace names and generated output path components when `kiota generate` ran without -c/--class-name, allowing an attacker-controlled or compromised OpenAPI description to write generated source outside the -o output directory and inject arbitrary text into generated class or namespace declarations. This issue is fixed in version 1.29.1 and 1.32.5 by GenerationConfiguration.SanitizeClientClassName and SanitizeClientNamespaceName.
Timeline
ID reserved
By GitHub_M
- 9 days later
· 9 days later
Published
- 32 days later
· 32 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 4.0 | Critical9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| NVDNVD · Deferred | 4.0 | Critical9.3 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 1.4% · top 27% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.3.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- NuGetMicrosoft.OpenApi.KiotaGHSA-4vv7-jj25-4gh6 (opens in a new tab)
- NuGetMicrosoft.OpenApi.Kiota.BuilderGHSA-4vv7-jj25-4gh6 (opens in a new tab)
References
References4
- https://github.com/microsoft/kiota/security/advisories/GHSA-4vv7-jj25-4gh6 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/microsoft/kiota/pull/7884 (opens in a new tab)x_refsource_MISC
- https://github.com/microsoft/kiota/commit/dc812dbbf88ef7edf53a890d36b2f9d1460e947d (opens in a new tab)x_refsource_MISC
- https://github.com/microsoft/kiota/releases/tag/v1.32.5 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-44936 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-4vv7-jj25-4gh6 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-59866)Record last updated .