CVE-2026-59860Public exploitNetwork attack vector

Code injection via XML doc-comment newline breakout

Published Jul 16, 2026 · Updated Jul 16, 2026

Code injection in Microsoft Kiota before 1.32.3 allows attackers to inject C# through crafted OpenAPI documentation text. CSharpConventionService emits description and externalDocs label and link text into single-line XML doc comments without stripping newline or Unicode line terminators. Exploitation requires an untrusted or tampered description and a developer or CI build, which compiles attacker-controlled C# into the generated client.

CVSS severity8.7
High
EPSS probability1.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Code injection in Microsoft Kiota before 1.32.3 allows attackers to inject C# through crafted OpenAPI documentation text. CSharpConventionService emits description and externalDocs label and link text into single-line XML doc comments without stripping newline or Unicode line terminators. Exploitation requires an untrusted or tampered description and a developer or CI build, which compiles attacker-controlled C# into the generated client.

The record

CVE
CVE-2026-59860
Published
Jul 16, 2026
Updated
Jul 16, 2026
Vendor
Microsoft
Product
Kiota
Classifications
CWE-94, T1204.002
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 16, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 16, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 1.32.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Kiotaversion=< 1.32.3

Published CVSS scores

8.7GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo