CVE-2026-22866

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{"affected": [{"affectedData": [{"product": "ens-contracts", "vendor": "ensdomains", "versions": [{"status": "affected", "version": "<= 1.6.2"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:ens.domains:ethereum_name_service:*:*:*:*:*:*:*:*", "matchCriteriaId": "DC6CB03A-8DF6-4B9E-9356-2850DBEC1913", "versionEndIncluding": "1.6.2", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Ethereum Name Service (ENS) is a distributed, open, and extensible naming system based on the Ethereum blockchain. In versions 1.6.2 and prior, the `RSASHA256Algorithm` and `RSASHA1Algorithm` contracts fail to validate PKCS#1 v1.5 padding structure when verifying RSA signatures. The contracts only check if the last 32 (or 20) bytes of the decrypted signature match the expected hash. This enables Bleichenbacher's 2006 signature forgery attack against DNS zones using RSA keys with low public exponents (e=3). Two ENS-supported TLDs (.cc and .name) use e=3 for their Key Signing Keys, allowing any domain under these TLDs to be fraudulently claimed on ENS without DNS ownership. Apatch was merged at commit c76c5ad0dc9de1c966443bd946fafc6351f87587. Possible workarounds include deploying the patched contracts and pointing DNSSECImpl.setAlgorithm to the deployed contract."}, {"lang": "es", "value": "El Servicio de Nombres de Ethereum (ENS) es un sistema de nombres distribuido, abierto y extensible basado en la cadena de bloques de Ethereum. En las versiones 1.6.2 y anteriores, los contratos 'RSASHA256Algorithm' y 'RSASHA1Algorithm' no logran validar la estructura de relleno PKCS#1 v1.5 al verificar firmas RSA. Los contratos solo verifican si los \u00faltimos 32 (o 20) bytes de la firma descifrada coinciden con el hash esperado. Esto permite el ataque de falsificaci\u00f3n de firmas de Bleichenbacher de 2006 contra zonas DNS que utilizan claves RSA con exponentes p\u00fablicos bajos (e=3). Dos TLDs compatibles con ENS (.cc y .name) usan e=3 para sus Claves de Firma de Claves, permitiendo que cualquier dominio bajo estos TLDs sea reclamado fraudulentamente en ENS sin la propiedad de DNS. Un parche fue fusionado en el commit c76c5ad0dc9de1c966443bd946fafc6351f87587. Posibles soluciones provisionales incluyen desplegar los contratos parcheados y apuntar DNSSECImpl.setAlgorithm al contrato desplegado."}], "id": "CVE-2026-22866", "lastModified": "2026-06-17T10:20:31.933", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "nvd@nist.gov", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 2.7, "baseSeverity": "LOW", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "UNREPORTED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "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:L/VA:N/SC:N/SI:N/SA:N/E:U/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", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-22866", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-02-25T20:33:54.551584Z", "version": "2.0.3"}}]}, "published": "2026-02-25T16:23:25.277", "references": [{"source": "security-advisories@github.com", "tags": ["Patch", "Release Notes"], "url": "https://github.com/ensdomains/ens-contracts-bug-62248-pr-509"}, {"source": "security-advisories@github.com", "tags": ["Patch"], "url": "https://github.com/ensdomains/ens-contracts/commit/c76c5ad0dc9de1c966443bd946fafc6351f87587"}, {"source": "security-advisories@github.com", "tags": ["Patch", "Vendor Advisory"], "url": "https://github.com/ensdomains/ens-contracts/security/advisories/GHSA-c6rr-7pmc-73wc"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-347"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.6.2]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "cna", "scores": [{"score": 100.0, "source": "cna"}]}, "original": {"product": "ens-contracts", "source": "cna", "vendor": "ensdomains"}, "product": "ens-contracts", "vendor": "ensdomains"}], "analysis": {"en": {"generated_at": "2026-04-17T15:12:06.129292+00:00", "value": {"mitigation_remediation": ["Deploy the patched ENS contracts from commit c76c5ad0dc9de1c966443bd946fafc6351f87587 and update the RSASHA256Algorithm and RSASHA1Algorithm libraries to the new implementation.", "Reconfigure DNSSECImpl.setAlgorithm to reference the newly deployed, patched contract implementation.", "Ensure that any ENS key signing key used for TLDs employs a secure public exponent (e.g., e\u202f=\u202f65537) or otherwise enforce PKCS#1 v1.5 padding validation in the contract."], "summary": {"action": "Apply Patch", "impact": "RSA Signature Forgery Leading to Domain Hijacking"}, "threat_synthesis": {"affected_systems": "The vulnerability affects the ENS name service contracts provided by ensdomains:ens-contracts, specifically the RSASHA256Algorithm and RSASHA1Algorithm contracts in releases 1.6.2 and earlier. ENS\u2011supported top\u2011level domains .cc and .name use the insecure e=3 key signing key and are thus directly impacted, but any ENS TLD that relies on the vulnerable contracts and a low public exponent is potentially susceptible.", "description_and_impact": "In ENS contracts version 1.6.2 and earlier, the RSASHA256Algorithm and RSASHA1Algorithm fail to validate PKCS#1 v1.5 padding when verifying RSA signatures, allowing the classic Bleichenbacher signature forgery to generate valid signatures for a chosen hash. This flaw permits an attacker to forge signatures that appear to originate from the legitimate key signing key, effectively enabling fraudulent registration of any sub\u2011domain under vulnerable TLDs that use a low public exponent, such as e=3. The result is a loss of integrity and authenticity of the ENS namespace, because domain ownership can be transferred from the rightful DNS holder to an adversary without access to the DNS zone. The flaw is a form of cryptographic weakness (CWE\u2011347).", "risk_and_exploitability": "The CVSS score is 2.7, indicating a low overall severity, and the EPSS score is less than 1\u202f%, implying a low probability of exploitation at present. The vulnerability is not listed in the CISA KEV catalog. Nevertheless, the attack is straightforward for an adversary willing to forge signatures, requiring only interaction with the ENS contracts and the ability to register the forged domain. The impact on domain ownership makes this a serious concern for TLD operators who continue to use the vulnerable contracts or low public exponents."}}}}, "created": "2026-02-26T13:15:48.733925+00:00", "updated": "2026-04-17T15:15:21.857509+00:00", "vendors": ["ensdomains", "ensdomains$PRODUCT$ens-contracts"]}