{"api_version":"1","generated_at":"2026-07-23T15:04:54+00:00","cve":"CVE-2023-42806","urls":{"html":"https://cve.report/CVE-2023-42806","api":"https://cve.report/api/cve/CVE-2023-42806.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2023-42806","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2023-42806"},"summary":{"title":"CVE-2023-42806","description":"Hydra is the layer-two scalability solution for Cardano. Prior to version 0.13.0, not signing and verifying `$\\mathsf{cid}$` allows an attacker (which must be a participant of this head) to use a snapshot from an old head instance with the same participants to close the head or contest the state with it. This can lead to an incorrect distribution of value (= value extraction attack; hard, but possible) or prevent the head to finalize because the value available is not consistent with the closed utxo state (= denial of service; easy). A patch is planned for version 0.13.0. As a workaround, rotate keys between heads so not to re-use keys and not result in the same multi-signature participants.","state":"PUBLIC","assigner":"security-advisories@github.com","published_at":"2023-09-21 17:15:00","updated_at":"2023-09-26 14:41:00"},"problem_types":["CWE-347"],"metrics":[],"references":[{"url":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-node/src/Hydra/Snapshot.hs#L50-L54","name":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-node/src/Hydra/Snapshot.hs#L50-L54","refsource":"MISC","tags":[],"title":"","mime":"text/plain","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-plutus/src/Hydra/Contract/Head.hs#L583-L599","name":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-plutus/src/Hydra/Contract/Head.hs#L583-L599","refsource":"MISC","tags":[],"title":"","mime":"text/plain","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-node/src/Hydra/HeadLogic.hs#L357","name":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-node/src/Hydra/HeadLogic.hs#L357","refsource":"MISC","tags":[],"title":"","mime":"text/plain","httpstatus":"200","archivestatus":"404"},{"url":"https://github.com/input-output-hk/hydra/security/advisories/GHSA-gr36-mc6v-72qq","name":"https://github.com/input-output-hk/hydra/security/advisories/GHSA-gr36-mc6v-72qq","refsource":"MISC","tags":[],"title":"Snapshot signature not including HeadID will allow replay attacks · Advisory · input-output-hk/hydra · GitHub","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2023-42806","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-42806","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2023","cve_id":"42806","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"iohk","cpe5":"hydra","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"data_version":"4.0","data_type":"CVE","data_format":"MITRE","CVE_data_meta":{"ID":"CVE-2023-42806","ASSIGNER":"security-advisories@github.com","STATE":"PUBLIC"},"description":{"description_data":[{"lang":"eng","value":"Hydra is the layer-two scalability solution for Cardano. Prior to version 0.13.0, not signing and verifying `$\\mathsf{cid}$` allows an attacker (which must be a participant of this head) to use a snapshot from an old head instance with the same participants to close the head or contest the state with it. This can lead to an incorrect distribution of value (= value extraction attack; hard, but possible) or prevent the head to finalize because the value available is not consistent with the closed utxo state (= denial of service; easy). A patch is planned for version 0.13.0. As a workaround, rotate keys between heads so not to re-use keys and not result in the same multi-signature participants."}]},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"CWE-347: Improper Verification of Cryptographic Signature","cweId":"CWE-347"}]}]},"affects":{"vendor":{"vendor_data":[{"vendor_name":"input-output-hk","product":{"product_data":[{"product_name":"hydra","version":{"version_data":[{"version_affected":"=","version_value":"< 0.13.0"}]}}]}}]}},"references":{"reference_data":[{"url":"https://github.com/input-output-hk/hydra/security/advisories/GHSA-gr36-mc6v-72qq","refsource":"MISC","name":"https://github.com/input-output-hk/hydra/security/advisories/GHSA-gr36-mc6v-72qq"},{"url":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-node/src/Hydra/HeadLogic.hs#L357","refsource":"MISC","name":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-node/src/Hydra/HeadLogic.hs#L357"},{"url":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-node/src/Hydra/Snapshot.hs#L50-L54","refsource":"MISC","name":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-node/src/Hydra/Snapshot.hs#L50-L54"},{"url":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-plutus/src/Hydra/Contract/Head.hs#L583-L599","refsource":"MISC","name":"https://github.com/input-output-hk/hydra/blob/ec6c7a2ab651462228475d0b34264e9a182c22bb/hydra-plutus/src/Hydra/Contract/Head.hs#L583-L599"}]},"source":{"advisory":"GHSA-gr36-mc6v-72qq","discovery":"UNKNOWN"},"impact":{"cvss":[{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"HIGH","privilegesRequired":"HIGH","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H","version":"3.1"}]}},"nvd":{"publishedDate":"2023-09-21 17:15:00","lastModifiedDate":"2023-09-26 14:41:00","problem_types":["CWE-347"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"HIGH","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM"},"exploitabilityScore":1.2,"impactScore":5.2}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:a:iohk:hydra:*:*:*:*:*:*:*:*","versionEndExcluding":"0.13.0","cpe_name":[]}]}]}},"legacy_mitre":{"record":null,"notes":[]}}}