Vulnerability-Lookup

GHSA-8FFR-XGWF-XJ56

Vulnerability from github – Published: 2026-10-02 22:44 – Updated: 2026-10-02 22:44

Summary

aws-smithy-json: Uncontrolled recursion in the aws-smithy-json unknown-key skip path allows unauthenticated remote denial of service in smithy-rs generated servers

Details

Summary

Smithy-RS is a Rust code generation and runtime framework that generates HTTP clients and servers from Smithy interface definitions, powering the AWS SDK for Rust and custom service implementations. An issue exists which allows uncontrolled recursion in the unknown-key skip path of the Amazon aws-smithy-json runtime crate in versions 0.62.6 and earlier.

Impact

Uncontrolled recursion in the unknown-key skip path of the aws-smithy-json runtime crate before 0.62.7, which the smithy-rs code generator invokes from every generated struct deserializer, might allow remote unauthenticated users to cause a denial of service (process abort via stack exhaustion) via a single small HTTP request containing deeply nested JSON to a smithy-rs generated server.

Impacted versions: aws-smithy-json <= 0.62.6

Patches

This issue has been addressed in aws-smithy-json version 0.62.7. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.

Workarounds

There are no workarounds besides updating to the patched version.

References

If you have any questions or comments about this advisory, AWS asks that you contact [AWS/Amazon] Security via their vulnerability reporting page or directly via email to aws-security@amazon.com. Please do not create a public GitHub issue.

Severity

7.5 (High)


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

8.7 (High)


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

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.62.6"
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "aws-smithy-json"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.62.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-18140"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-674"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-02T22:44:52Z",
    "nvd_published_at": "2026-07-30T19:17:26Z",
    "severity": "HIGH"
  },
  "details": "### Summary\nSmithy-RS is a Rust code generation and runtime framework that generates HTTP clients and servers from Smithy interface definitions, powering the AWS SDK for Rust and custom service implementations. An issue exists which allows uncontrolled recursion in the unknown-key skip path of the Amazon aws-smithy-json runtime crate in versions 0.62.6 and earlier.\n\n### Impact\nUncontrolled recursion in the unknown-key skip path of the aws-smithy-json runtime crate before 0.62.7, which the smithy-rs code generator invokes from every generated struct deserializer, might allow remote unauthenticated users to cause a denial of service (process abort via stack exhaustion) via a single small HTTP request containing deeply nested JSON to a smithy-rs generated server.\n\nImpacted versions: aws-smithy-json \u003c= 0.62.6\n\n### Patches\nThis issue has been addressed in aws-smithy-json version 0.62.7. We recommend upgrading to the latest version and ensuring any forked or derivative code is patched to incorporate the new fixes.\n\n### Workarounds\nThere are no workarounds besides updating to the patched version.\n\n### References\nIf you have any questions or comments about this advisory, AWS asks that you contact [AWS/Amazon] Security via their [vulnerability reporting page](https://aws.amazon.com/security/vulnerability-reporting) or directly via email to [aws-security@amazon.com](mailto:aws-security@amazon.com). Please do not create a public GitHub issue.",
  "id": "GHSA-8ffr-xgwf-xj56",
  "modified": "2026-10-02T22:44:52Z",
  "published": "2026-10-02T22:44:52Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/smithy-lang/smithy-rs/security/advisories/GHSA-8ffr-xgwf-xj56"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-18140"
    },
    {
      "type": "WEB",
      "url": "https://github.com/smithy-lang/smithy-rs/pull/4685"
    },
    {
      "type": "WEB",
      "url": "https://github.com/smithy-lang/smithy-rs/commit/8f0882046c467981ba5b4fd91a10befa96bd262f"
    },
    {
      "type": "WEB",
      "url": "https://aws.amazon.com/security/security-bulletins/2026-067-aws"
    },
    {
      "type": "WEB",
      "url": "https://crates.io/crates/aws-smithy-json/0.62.7"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/smithy-lang/smithy-rs"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "aws-smithy-json: Uncontrolled recursion in the aws-smithy-json unknown-key skip path allows unauthenticated remote denial of service in smithy-rs generated servers"
}

CVE-2026-18140 (GCVE-0-2026-18140)

Vulnerability from cvelistv5 – Published: 2026-07-30 18:34 – Updated: 2026-07-30 19:12

Title

Uncontrolled recursion in the aws-smithy-json unknown-key skip path allows unauthenticated remote denial of service in smithy-rs generated servers

Summary

Severity

7.5 (High)


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

8.7 (High)


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

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-30 19:12 UTC

CWE

CWE-674 - Uncontrolled Recursion

Assigner

AMZN CNA under the mitre root

CNA scorecard A 93/100 over 129 records in the last 180 days details

References

3 references

URL	Tags
https://crates.io/crates/aws-smithy-json/0.62.7	patch
https://aws.amazon.com/security/security-bulletin…	vendor-advisory
https://github.com/smithy-lang/smithy-rs/security…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
AWS	aws-smithy-json	Affected: 0.32.0 , ≤ 0.62.6 (custom) cpe:2.3:a:aws:aws-smithy-json::::::::

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-18140",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-30T19:12:34.733029Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-07-30T19:12:50.560Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "aws-smithy-json",
          "vendor": "AWS",
          "versions": [
            {
              "lessThanOrEqual": "0.62.6",
              "status": "affected",
              "version": "0.32.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:aws:aws-smithy-json:*:*:*:*:*:*:*:*",
                  "versionEndIncluding": "0.62.6",
                  "versionStartIncluding": "0.32.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ],
          "operator": "OR"
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "supportingMedia": [
            {
              "base64": false,
              "type": "text/html",
              "value": "\u003cp\u003eUncontrolled recursion in the unknown-key skip path of the aws-smithy-json runtime crate before 0.62.7, which the smithy-rs code generator invokes from every generated struct deserializer, might allow remote unauthenticated users to cause a denial of service (process abort via stack exhaustion) via a single small HTTP request containing deeply nested JSON to a smithy-rs generated server.\u003c/p\u003e\u003cp\u003eTo remediate this issue, users should upgrade to aws-smithy-json 0.62.7 or later and rebuild.\u003c/p\u003e"
            }
          ],
          "value": "Uncontrolled recursion in the unknown-key skip path of the aws-smithy-json runtime crate before 0.62.7, which the smithy-rs code generator invokes from every generated struct deserializer, might allow remote unauthenticated users to cause a denial of service (process abort via stack exhaustion) via a single small HTTP request containing deeply nested JSON to a smithy-rs generated server.\n\n\n\nTo remediate this issue, users should upgrade to aws-smithy-json 0.62.7 or later and rebuild."
        }
      ],
      "impacts": [
        {
          "capecId": "CAPEC-230",
          "descriptions": [
            {
              "lang": "en",
              "value": "CAPEC-230: Serialized Data with Nested Payloads"
            }
          ]
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        },
        {
          "cvssV4_0": {
            "Automatable": "NOT_DEFINED",
            "Recovery": "NOT_DEFINED",
            "Safety": "NOT_DEFINED",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "attackVector": "NETWORK",
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "exploitMaturity": "NOT_DEFINED",
            "privilegesRequired": "NONE",
            "providerUrgency": "NOT_DEFINED",
            "subAvailabilityImpact": "NONE",
            "subConfidentialityImpact": "NONE",
            "subIntegrityImpact": "NONE",
            "userInteraction": "NONE",
            "valueDensity": "NOT_DEFINED",
            "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "version": "4.0",
            "vulnAvailabilityImpact": "HIGH",
            "vulnConfidentialityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "vulnerabilityResponseEffort": "NOT_DEFINED"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-674",
              "description": "CWE-674: Uncontrolled Recursion",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-07-30T18:34:04.099Z",
        "orgId": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
        "shortName": "AMZN"
      },
      "references": [
        {
          "tags": [
            "patch"
          ],
          "url": "https://crates.io/crates/aws-smithy-json/0.62.7"
        },
        {
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://aws.amazon.com/security/security-bulletins/2026-067-aws/"
        },
        {
          "tags": [
            "third-party-advisory"
          ],
          "url": "https://github.com/smithy-lang/smithy-rs/security/advisories/GHSA-8ffr-xgwf-xj56"
        }
      ],
      "source": {
        "discovery": "UNKNOWN"
      },
      "title": "Uncontrolled recursion in the aws-smithy-json unknown-key skip path allows unauthenticated remote denial of service in smithy-rs generated servers",
      "x_generator": {
        "engine": "Vulnogram 1.0.4"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "ff89ba41-3aa1-4d27-914a-91399e9639e5",
    "assignerShortName": "AMZN",
    "cveId": "CVE-2026-18140",
    "datePublished": "2026-07-30T18:34:04.099Z",
    "dateReserved": "2026-07-28T18:30:40.451Z",
    "dateUpdated": "2026-07-30T19:12:50.560Z",
    "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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Action not permitted

GHSA-8FFR-XGWF-XJ56

Summary

Impact

Patches

Workarounds

References

CVE-2026-18140 (GCVE-0-2026-18140)

Tags

Sightings

Nomenclature

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