Kiota: Code Generation Literal Injection in Kiota Ruby Generator

published 2026-07-16 3 mo ago modified 2026-10-24 15 d ago also EUVD-2026-44926 , GHSA-xg2h-5xr2-29jw

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.0%; EPSS 2.0% chance of exploitation in 30 days, percentile 81%
public exploits: 0; none known

Kiota is an OpenAPI based HTTP Client code generator. Prior to 1.29.1 and 1.32.0, Kiota's Ruby generator embedded OpenAPI default fields, property names, and other schema-derived strings through CodeMethodWriter.cs and SanitizeForQuotedLiteral() in Writers/StringExtensions.cs into Ruby double-quoted literals without escaping #, allowing attacker-controlled #{expr}, #$var, or #@var interpolation markers to inject arbitrary Ruby code into generated model classes. This issue is fixed in version 1.29.1 and 1.32.0.

Patch / fix

fixed in 7 links 3

nuget Microsoft.OpenAPI.Kiota 1.32.0
nuget Microsoft.OpenAPI.Kiota.Builder 1.32.0
nuget Microsoft.OpenApi.Kiota 1.29.1
nuget Microsoft.OpenApi.Kiota.Builder 1.29.1
microsoft kiota 1.29.1, 1.32.0
microsoft microsoft.openapi.kiota 1.29.1, 1.32.0
microsoft microsoft.openapi.kiota.builder 1.29.1, 1.32.0

github.com/microsoft/kiota@fee1b64 commit
github.com/microsoft/kiota#7746 pull request
github.com/microsoft/kiota/releases/tag/v1.32.0 release

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: total
Assessed: 3 mo ago (2026-07-17)

Exploit prediction

2.05% chance of exploitation in the next 30 days, higher than 81% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem	package	affected	fixed in
nuget	Microsoft.OpenAPI.Kiota	>=1.30.0, <1.32.0	1.32.0
nuget	Microsoft.OpenAPI.Kiota.Builder	>=1.30.0, <1.32.0	1.32.0
nuget	Microsoft.OpenApi.Kiota	<1.29.1	1.29.1
nuget	Microsoft.OpenApi.Kiota.Builder	<1.29.1	1.29.1

Affected products

microsoft kiota

Classification

Weakness

CWE-94 Improper Control of Generation of Code

References

Sources

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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary