{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-54904",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-06-16T13:49:33.556Z",
        "datePublished": "2026-06-24T15:44:21.992Z",
        "dateUpdated": "2026-08-05T17:36:28.452Z"
    },
    "containers": {
        "cna": {
            "title": "concurrent-ruby:  `AtomicReference#update` livelocks when the stored value is `Float::NAN`",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-835",
                            "lang": "en",
                            "description": "CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "PRESENT",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "NONE",
                        "vulnAvailabilityImpact": "HIGH",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "subAvailabilityImpact": "NONE",
                        "baseScore": 8.2,
                        "baseSeverity": "HIGH",
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
                        "version": "4.0"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-h8w8-99g7-qmvj",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-h8w8-99g7-qmvj"
                },
                {
                    "name": "https://github.com/ruby-concurrency/concurrent-ruby/commit/6e37e0644b83b182971dc540d2e4bee38df61386",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/ruby-concurrency/concurrent-ruby/commit/6e37e0644b83b182971dc540d2e4bee38df61386"
                },
                {
                    "name": "https://github.com/ruby-concurrency/concurrent-ruby/releases/tag/v1.3.7",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/ruby-concurrency/concurrent-ruby/releases/tag/v1.3.7"
                },
                {
                    "name": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/concurrent-ruby/CVE-2026-54904.yml",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/concurrent-ruby/CVE-2026-54904.yml"
                }
            ],
            "affected": [
                {
                    "vendor": "ruby-concurrency",
                    "product": "concurrent-ruby",
                    "versions": [
                        {
                            "version": "< 1.3.7",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-08-05T17:36:28.452Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "concurrent-ruby is a modern concurrency tools for Ruby. Prior to 1.3.7, Concurrent::AtomicReference#update can enter a permanent busy retry loop when the current value is Float::NAN. The issue is caused by the interaction between AtomicReference#update, which retries until compare_and_set(old_value, new_value) succeeds; Numeric compare_and_set, which checks old == old_value before attempting the underlying atomic swap.; and Ruby NaN semantics, where Float::NAN == Float::NAN is always false. As a result, once an AtomicReference contains Float::NAN, calling #update repeatedly evaluates the caller's block and never returns. In services that store externally derived numeric values in an AtomicReference, this can cause CPU exhaustion or permanent request/job hangs. This vulnerability is fixed in 1.3.7."
                }
            ],
            "source": {
                "advisory": "GHSA-h8w8-99g7-qmvj",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/ruby-concurrency/concurrent-ruby/security/advisories/GHSA-h8w8-99g7-qmvj",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-06-25T13:19:55.812897Z",
                                "id": "CVE-2026-54904",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-06-25T13:20:00.135Z"
                }
            }
        ]
    }
}