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CVE-2026-41134: Microsoft Kiota Code Injection (CVSS 7.3)

CVE-2026-41134 is a high severity code injection in Microsoft Kiota with a CVSS score of 7.3. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Last updated: Aug 17, 2026

Quick answer

Direct answer

CVE-2026-41134 is a high severity code injection in Microsoft Kiota with a CVSS score of 7.3. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Risk scores

CVSS base score
7.3HIGH
EPSS probability
0.35%
Higher than 27 percent of all CVEs
CISA KEV
Not listed
CVSS metricWhat it means
Attack vector (AV:L)Local access needed
Attack complexity (AC:L)Low complexity
Attack requirements (AT:P)Attack requirements present
Privileges required (PR:N)No privileges required
User interaction (UI:P)Passive user interaction
Confidentiality (VC:H)High confidentiality impact
Integrity (VI:H)High integrity impact
Availability (VA:H)High availability impact

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/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

About Microsoft Kiota

CVE-2026-41134 affects Microsoft Kiota, a product from Microsoft. Before acting, confirm where Microsoft Kiota runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.

What the flaw is

In plain terms: Kiota is an OpenAPI based HTTP Client code generator. Versions prior to 1.29.1 and 1.31.1 are affected by a code-generation literal injection vulnerability in multiple writer sinks (for example: serialization/deserialization keys, path/query parameter mappings, URL template metadata, enum/property metadata, and default value emission). When malicious values from an OpenAPI description are emitted into generated source without context-appropriate escaping, an attacker can break out of string literals and inject additional code into generated clients. This issue is only practically exploitable when the OpenAPI description used for generation is from an untrusted source, or a normally trusted OpenAPI description has been compromised/tampered with. Only generating from trusted, integrity-protected API descriptions significantly reduces the risk. To remediate the issue, upgrade Kiota to 1.29.1, 1.31.1, or later and regenerate/refresh existing generated clients as a precaution. Refreshing generated clients ensures previously generated vulnerable code is replaced with hardened output.

The weakness class is Code Injection. Attacker input is executed as program code.

Based on its CVSS vector, the flaw needs local or adjacent access, needs no login, and relies on a user taking an action. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

Affected versions and timeline

FieldDetail
ProductMicrosoft Kiota
Affected versionsKiota before 1.31.1
PublishedApr 22, 2026
Last modifiedAug 17, 2026
Added to CISA KEVNot listed
Assigning CNAsecurity-advisories@github.com

How to detect it

  • Inventory every instance of Microsoft Kiota and record the running version against the affected range above.
  • Check external attack surface scans for internet facing instances of the component.
  • Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
  • Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.

How to fix it

  • Apply the fixed version of Microsoft Kiota named in the vendor advisory.
  • If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
  • Rescan after the change to prove the exposure is gone, then close the ticket.

CTEM action plan

CTEM stageWhat to do for this CVE
ScopeAdd every business service that depends on Microsoft Kiota to the current CTEM cycle.
DiscoverFind all instances, including shadow and cloud deployments, and record versions and exposure.
PrioritizeRank using EPSS and CVSS together with asset exposure and business impact.
ValidateConfirm the flaw is reachable and exploitable in your environment and that compensating controls work.
MobilizeAssign the fix to the asset owner with a due date matched to the priority, then verify closure.

CWE References

Technical References

Frequently asked questions

CVE-2026-41134 is a high severity code injection in Microsoft Kiota with a CVSS score of 7.3. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.

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