Vulnerability-Lookup

GHSA-RM89-RHWJ-9J92

Vulnerability from github – Published: 2026-10-06 15:36 – Updated: 2026-10-06 15:36

Summary

Kiota: Code injection through doc-comment delimiter reformation in Kiota Java and PHP generators

Details

Impact

An attacker who controls or tampers with an OpenAPI description can cause Kiota to emit attacker-controlled Java or PHP source outside a generated documentation comment. The affected sanitizers remove comment terminators rather than neutralizing them, allowing a terminator to reform from overlapping characters or from subsequent normalization. The Java sanitizer also removes non-ASCII characters after removing terminators, which can create a new terminator.

Exploitation requires a developer or build pipeline to generate a client from the malicious description and subsequently compile and load the Java output, or load the PHP output. Code executes in the consuming application's or build environment's security context, not merely because Kiota reads the description.

Affected versions

The affected NuGet packages are Microsoft.OpenApi.Kiota and Microsoft.OpenApi.Kiota.Builder. The Java normalization-order defect was introduced in version 0.5.0 and remains present through version 1.34.1, including the separate 1.29.1 security-backport release. The PHP delimiter-reformation variant is also present in version 1.34.1 and 1.29.1. Version 1.35.0 fixes both variants.

The package version range below reflects the Java defect; it does not assert that PHP generation existed in every version in that range.

Patches

Upgrade to Kiota 1.35.0 or later and regenerate affected clients. The fix neutralizes block-comment delimiters instead of deleting them, and performs Java delimiter neutralization after non-ASCII normalization.

Fix: https://github.com/microsoft/kiota/pull/8017
Fixed release: https://github.com/microsoft/kiota/releases/tag/v1.35.0

Workarounds

Until upgrading, generate clients only from trusted, integrity-protected OpenAPI descriptions. Review generated Java and PHP source before compiling, loading, or deploying it. Restrict the privileges and secrets available to generation and build environments.

Related advisories

This is distinct from PHP double-quoted string interpolation (GHSA-jqwh-526h-c92j) and C# XML documentation newline breakout (GHSA-3hrf-2gc2-mx32). Those fixes do not address Java/PHP block-comment delimiter reformation.

Severity

8.8 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

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{
  "affected": [
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.OpenApi.Kiota"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.5.0"
            },
            {
              "fixed": "1.35.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "NuGet",
        "name": "Microsoft.OpenApi.Kiota.Builder"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.5.0"
            },
            {
              "fixed": "1.35.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-105796"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-06T15:36:00Z",
    "nvd_published_at": "2026-10-06T15:17:16Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nAn attacker who controls or tampers with an OpenAPI description can cause Kiota to emit attacker-controlled Java or PHP source outside a generated documentation comment. The affected sanitizers remove comment terminators rather than neutralizing them, allowing a terminator to reform from overlapping characters or from subsequent normalization. The Java sanitizer also removes non-ASCII characters after removing terminators, which can create a new terminator.\n\nExploitation requires a developer or build pipeline to generate a client from the malicious description and subsequently compile and load the Java output, or load the PHP output. Code executes in the consuming application\u0027s or build environment\u0027s security context, not merely because Kiota reads the description.\n\n### Affected versions\n\nThe affected NuGet packages are `Microsoft.OpenApi.Kiota` and `Microsoft.OpenApi.Kiota.Builder`. The Java normalization-order defect was introduced in version 0.5.0 and remains present through version 1.34.1, including the separate 1.29.1 security-backport release. The PHP delimiter-reformation variant is also present in version 1.34.1 and 1.29.1. Version 1.35.0 fixes both variants.\n\nThe package version range below reflects the Java defect; it does not assert that PHP generation existed in every version in that range.\n\n### Patches\n\nUpgrade to Kiota 1.35.0 or later and regenerate affected clients. The fix neutralizes block-comment delimiters instead of deleting them, and performs Java delimiter neutralization after non-ASCII normalization.\n\n- Fix: https://github.com/microsoft/kiota/pull/8017\n- Fixed release: https://github.com/microsoft/kiota/releases/tag/v1.35.0\n\n### Workarounds\n\nUntil upgrading, generate clients only from trusted, integrity-protected OpenAPI descriptions. Review generated Java and PHP source before compiling, loading, or deploying it. Restrict the privileges and secrets available to generation and build environments.\n\n### Related advisories\n\nThis is distinct from PHP double-quoted string interpolation (GHSA-jqwh-526h-c92j) and C# XML documentation newline breakout (GHSA-3hrf-2gc2-mx32). Those fixes do not address Java/PHP block-comment delimiter reformation.",
  "id": "GHSA-rm89-rhwj-9j92",
  "modified": "2026-10-06T15:36:00Z",
  "published": "2026-10-06T15:36:00Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/microsoft/kiota/security/advisories/GHSA-rm89-rhwj-9j92"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-105796"
    },
    {
      "type": "WEB",
      "url": "https://github.com/microsoft/kiota/pull/8017"
    },
    {
      "type": "WEB",
      "url": "https://github.com/microsoft/kiota/commit/68f33b865be9273464a6efbbe17379760e51f1a4"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/microsoft/kiota"
    },
    {
      "type": "WEB",
      "url": "https://github.com/microsoft/kiota/releases/tag/v1.35.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Kiota: Code injection through doc-comment delimiter reformation in Kiota Java and PHP generators"
}

CVE-2026-105796 (GCVE-0-2026-105796)

Vulnerability from cvelistv5 – Published: 2026-10-06 14:21 – Updated: 2026-10-09 01:03

Title

Kiota: Code injection through doc-comment delimiter reformation in Kiota Java and PHP generators

Summary

Kiota is an OpenAPI based HTTP Client code generator. From 0.5.0 until 1.35.0, Kiota's Java and PHP documentation-comment sanitizers delete block-comment terminators rather than neutralizing them, allowing overlapping characters to reform a terminator and place attacker-controlled OpenAPI text outside a generated documentation comment. The Java sanitizer also removes non-ASCII characters after deleting terminators, which can create a new terminator during normalization. Exploitation requires a developer or build pipeline to generate source from the malicious description and then compile and load the Java output or load the PHP output, after which injected code executes in the consuming application or build environment context. The version range is based on the Java defect and does not assert that PHP generation existed in every affected release. This issue is fixed in version 1.35.0.

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-10-09 01:03 UTC

CWE

CWE-94 - Improper Control of Generation of Code ('Code Injection')

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7580 records in the last 180 days details

References

4 references

URL	Tags
https://github.com/microsoft/kiota/security/advis…	x_refsource_CONFIRM
https://github.com/microsoft/kiota/pull/8017	x_refsource_MISC
https://github.com/microsoft/kiota/commit/68f33b8…	x_refsource_MISC
https://github.com/microsoft/kiota/releases/tag/v1.35.0	x_refsource_MISC

Impacted products

3 products

Vendor	Product	Version
microsoft	kiota	Affected: >= 0.5.0, < 1.35.0
microsoft	Microsoft.OpenApi.Kiota	Affected: >= 0.5.0, < 1.35.0
microsoft	Microsoft.OpenApi.Kiota.Builder	Affected: >= 0.5.0, < 1.35.0

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-105796",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-10-09T01:03:40.299954Z",
                "version": "2.0.3"
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              "type": "ssvc"
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        "providerMetadata": {
          "dateUpdated": "2026-10-09T01:03:51.338Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
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      }
    ],
    "cna": {
      "affected": [
        {
          "product": "kiota",
          "vendor": "microsoft",
          "versions": [
            {
              "status": "affected",
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            }
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        },
        {
          "product": "Microsoft.OpenApi.Kiota.Builder",
          "vendor": "microsoft",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 0.5.0, \u003c 1.35.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Kiota is an OpenAPI based HTTP Client code generator. From 0.5.0 until 1.35.0, Kiota\u0027s Java and PHP documentation-comment sanitizers delete block-comment terminators rather than neutralizing them, allowing overlapping characters to reform a terminator and place attacker-controlled OpenAPI text outside a generated documentation comment. The Java sanitizer also removes non-ASCII characters after deleting terminators, which can create a new terminator during normalization. Exploitation requires a developer or build pipeline to generate source from the malicious description and then compile and load the Java output or load the PHP output, after which injected code executes in the consuming application or build environment context. The version range is based on the Java defect and does not assert that PHP generation existed in every affected release. This issue is fixed in version 1.35.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-94",
              "description": "CWE-94: Improper Control of Generation of Code (\u0027Code Injection\u0027)",
              "lang": "en",
              "type": "CWE"
            }
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      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-06T14:21:42.684Z",
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        {
          "name": "https://github.com/microsoft/kiota/pull/8017",
          "tags": [
            "x_refsource_MISC"
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          "url": "https://github.com/microsoft/kiota/pull/8017"
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          "url": "https://github.com/microsoft/kiota/commit/68f33b865be9273464a6efbbe17379760e51f1a4"
        },
        {
          "name": "https://github.com/microsoft/kiota/releases/tag/v1.35.0",
          "tags": [
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          "url": "https://github.com/microsoft/kiota/releases/tag/v1.35.0"
        }
      ],
      "source": {
        "advisory": "GHSA-rm89-rhwj-9j92",
        "discovery": "UNKNOWN"
      },
      "title": "Kiota: Code injection through doc-comment delimiter reformation in Kiota Java and PHP generators"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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    "datePublished": "2026-10-06T14:21:42.684Z",
    "dateReserved": "2026-10-05T20:37:19.364Z",
    "dateUpdated": "2026-10-09T01:03:51.338Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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