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.
To remediate this issue, users should upgrade to aws-smithy-json 0.62.7 or later and rebuild.
"}],"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"},"nvd":{"publishedDate":"2026-07-30 19:17:26","lastModifiedDate":"2026-08-10 20:04:05","problem_types":["CWE-674","CWE-674 CWE-674: Uncontrolled Recursion"],"metrics":{"cvssMetricV40":[{"source":"ff89ba41-3aa1-4d27-914a-91399e9639e5","type":"Secondary","cvssData":{"version":"4.0","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/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","baseScore":8.7,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"cvssMetricV31":[{"source":"ff89ba41-3aa1-4d27-914a-91399e9639e5","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-07-30T19:12:34.733029Z","id":"CVE-2026-18140","options":[{"exploitation":"none"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:amazon:aws-smithy-json:*:*:*:*:*:rust:*:*","versionEndExcluding":"0.62.7","matchCriteriaId":"BDC78F08-F0CF-4631-931C-7C24AB4257FC"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"18140","Ordinal":"1","Title":"Uncontrolled recursion in the aws-smithy-json unknown-key skip p","CVE":"CVE-2026-18140","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"18140","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Uncontrolled recursion in the aws-smithy-json unknown-key skip p"}]}}}