CVE-2026-126366

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-126366", "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "state": "PUBLISHED", "assignerShortName": "GitHub_M", "dateReserved": "2026-11-10T21:12:01.228Z", "datePublished": "2026-11-12T22:41:38.409Z", "dateUpdated": "2026-11-12T22:41:38.409Z"}, "containers": {"cna": {"title": "msgpack-java JRuby decoder allocates from declared header counts with no cap: 5-byte message forces multi-GiB OOM", "problemTypes": [{"descriptions": [{"cweId": "CWE-770", "lang": "en", "description": "CWE-770: Allocation of Resources Without Limits or Throttling", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-1325", "lang": "en", "description": "CWE-1325: Improperly Controlled Sequential Memory Allocation", "type": "CWE"}]}], "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"}}], "references": [{"name": "https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-73v3-wf97-vpgj", "tags": ["x_refsource_CONFIRM"], "url": "https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-73v3-wf97-vpgj"}, {"name": "https://github.com/msgpack/msgpack-ruby/commit/ca0efc1256c687b428c46dd68ce000ff515d53f2", "tags": ["x_refsource_MISC"], "url": "https://github.com/msgpack/msgpack-ruby/commit/ca0efc1256c687b428c46dd68ce000ff515d53f2"}, {"name": "https://github.com/msgpack/msgpack-ruby/releases/tag/v1.8.6", "tags": ["x_refsource_MISC"], "url": "https://github.com/msgpack/msgpack-ruby/releases/tag/v1.8.6"}, {"name": "https://github.com/msgpack/msgpack-ruby/releases/tag/v1.8.7", "tags": ["x_refsource_MISC"], "url": "https://github.com/msgpack/msgpack-ruby/releases/tag/v1.8.7"}], "affected": [{"vendor": "msgpack", "product": "msgpack-ruby", "versions": [{"version": "< 1.8.7", "status": "affected"}]}], "providerMetadata": {"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa", "shortName": "GitHub_M", "dateUpdated": "2026-11-12T22:41:38.409Z"}, "descriptions": [{"lang": "en", "value": "MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.7, the Java-platform msgpack gem for JRuby allocated arrays and byte buffers directly from attacker-controlled array32, str32, and bin32 declared sizes before confirming that corresponding elements or bytes were available. A short MessagePack header could therefore trigger a very large allocation or sustained heap growth when an application decoded untrusted input through MessagePack.unpack or MessagePack::Unpacker, potentially exhausting the shared JVM heap. map32 and declared counts at or above 2^31 did not use the affected allocation behavior. This issue is fixed in version 1.8.7."}], "source": {"advisory": "GHSA-73v3-wf97-vpgj", "discovery": "UNKNOWN"}}}}

{}

{"affected": [{"affectedData": [{"product": "msgpack-ruby", "vendor": "msgpack", "versions": [{"status": "affected", "version": "< 1.8.7"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "MessagePack for Ruby is an implementation of the MessagePack binary serialization format. Prior to 1.8.7, the Java-platform msgpack gem for JRuby allocated arrays and byte buffers directly from attacker-controlled array32, str32, and bin32 declared sizes before confirming that corresponding elements or bytes were available. A short MessagePack header could therefore trigger a very large allocation or sustained heap growth when an application decoded untrusted input through MessagePack.unpack or MessagePack::Unpacker, potentially exhausting the shared JVM heap. map32 and declared counts at or above 2^31 did not use the affected allocation behavior. This issue is fixed in version 1.8.7."}], "id": "CVE-2026-126366", "lastModified": "2026-11-13T00:20:12.397", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "security-advisories@github.com", "type": "Secondary"}]}, "published": "2026-11-13T00:20:12.397", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/msgpack/msgpack-ruby/commit/ca0efc1256c687b428c46dd68ce000ff515d53f2"}, {"source": "security-advisories@github.com", "url": "https://github.com/msgpack/msgpack-ruby/releases/tag/v1.8.6"}, {"source": "security-advisories@github.com", "url": "https://github.com/msgpack/msgpack-ruby/releases/tag/v1.8.7"}, {"source": "security-advisories@github.com", "url": "https://github.com/msgpack/msgpack-ruby/security/advisories/GHSA-73v3-wf97-vpgj"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-770"}, {"lang": "en", "value": "CWE-1325"}], "source": "security-advisories@github.com", "type": "Primary"}]}

{}

{}