CVE-2026-22866: @ensdomains/ens contracts ENS DNSSEC Oracle Vulnerable To Vulnerability

LOW
Advisory Identifier: GHSA-c6rr-7pmc-73wc
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CWE-347
Published
Advisory Summary

CVE-2026-22866 is a LOW ens dnssec oracle vulnerable to vulnerability (CWE-347: Improper Verification of Cryptographic Signature) affecting @ensdomains/ens contracts libraries in the npm ecosystem. The issue involves ens dnssec oracle vulnerable to rsa signature forgery via missing pkcs#1 v1.5 padding validation. Remediation is available in the latest vendor maintenance releases.

CVE-2026-22866 at a Glance

CVE Identifier CVE-2026-22866
GHSA Identifier GHSA-c6rr-7pmc-73wc
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-347: Improper Verification of Cryptographic Signature
Affected Product @ensdomains/ens contracts
Package Ecosystem npm
Published Date
Last Updated

How to Fix CVE-2026-22866

To remediate this vulnerability, upgrade all affected @ensdomains/ens contracts dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

@ensdomains/ens-contracts fixed: Latest secure release 
npm install @ensdomains/ens-contracts@Latest secure release
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

npm ls @ensdomains/ens-contracts

How to Check if You Are Affected

To determine whether your Node.js application is affected by CVE-2026-22866, inspect your project dependencies using npm:

npm ls @ensdomains/ens-contracts

Analyze the terminal output to locate any version of @ensdomains/ens contracts in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The npm ls @ensdomains/ens-contracts command inspects dependencies declared in your package.json and lockfile; it does not perform automated runtime dynamic scanning.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-347: Improper Verification of Cryptographic Signature, where the product does not verify, or incorrectly verifies, the cryptographic signature for data. In @ensdomains/ens contracts, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Impact 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. Affected contracts Contract | Address | Status -- | -- | -- RSASHA256Algorithm | 0x9D1B5a639597f558bC37Cf81813724076c5C1e96 | Vulnerable RSASHA1Algorithm | 0x6ca8624Bc207F043D140125486De0f7E624e37A1 | Vulnerable DNSSECImpl | 0x0fc3152971714E5ed7723FAFa650F86A4BaF30C5 | Uses vulnerable algorithms DNSRegistrar | 0xB32cB5677a7C971689228EC835800432B339bA2B | Attack entry point ### Patches The bug was reported via Immunefi with possible solutions. The patch was merged at https://github.com/ensdomains/ens-contracts/commit/c76c5ad0dc9de1c966443bd946fafc6351f87587 ### Workarounds - Deploy the patched contracts - Point DNSSECImpl.setAlgorithm to the deployed contract ### Resources https://github.com/ensdomains/ens-contracts-bug-62248-pr-509

CVE-2026-22866 Affected @ensdomains/ens contracts Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
@ensdomains/ens-contracts
npm/@ensdomains/ens-contracts
npm
≤ 1.6.2

References

GitHub Advisory / Wiki ADVISORY
https://github.com/ensdomains/ens-contracts/security/advisories/GHSA-c6rr-7pmc-73wc
NVD — CVE-2026-22866 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-22866
Security Fix Commit FIX COMMIT
https://github.com/ensdomains/ens-contracts/commit/c76c5ad0dc9de1c966443bd946fafc6351f87587
@ensdomains/ens contracts Source Repository REPOSITORY
https://github.com/ensdomains/ens-contracts
@ensdomains/ens contracts Source Repository REPOSITORY
https://github.com/ensdomains/ens-contracts-bug-62248-pr-509

Frequently Asked Questions

What is CVE-2026-22866?
CVE-2026-22866 is a security vulnerability in @ensdomains/ens contracts involving ENS DNSSEC Oracle Vulnerable to RSA Signature Forgery via Missing PKCS#1 v1.5 Padding Validation under CWE-347: Improper Verification of Cryptographic Signature.
Which @ensdomains/ens contracts versions are affected?
Affected versions include releases prior to current release patches across affected packages: @ensdomains/ens-contracts.
What version fixes CVE-2026-22866?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is @ensdomains/ens-contracts affected?
Yes, @ensdomains/ens-contracts is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What CWE is associated with CVE-2026-22866?
CVE-2026-22866 is classified under CWE-347: Improper Verification of Cryptographic Signature (The product does not verify, or incorrectly verifies, the cryptographic signature for data.).
How can I check npm dependencies for CVE-2026-22866?
Run the dependency tree command: 'npm ls @ensdomains/ens-contracts'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-c6rr-7pmc-73wc",
  "modified" : "2026-02-27T20:55:13Z",
  "published" : "2026-02-25T18:26:58Z",
  "aliases" : [ "CVE-2026-22866" ],
  "summary" : "ENS DNSSEC Oracle Vulnerable to RSA Signature Forgery via Missing PKCS#1 v1.5 Padding Validation",
  "details" : "### Impact\n\nThe `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.\n\nAffected contracts\n\nContract | Address | Status\n-- | -- | --\nRSASHA256Algorithm | 0x9D1B5a639597f558bC37Cf81813724076c5C1e96 | Vulnerable\nRSASHA1Algorithm | 0x6ca8624Bc207F043D140125486De0f7E624e37A1 | Vulnerable\nDNSSECImpl | 0x0fc3152971714E5ed7723FAFa650F86A4BaF30C5 | Uses vulnerable algorithms\nDNSRegistrar | 0xB32cB5677a7C971689228EC835800432B339bA2B | Attack entry point\n\n\n\n\n### Patches\n\nThe bug was reported via Immunefi with possible solutions. The patch was merged at https://github.com/ensdomains/ens-contracts/commit/c76c5ad0dc9de1c966443bd946fafc6351f87587\n\n\n### Workarounds\n\n- Deploy the patched contracts\n- Point DNSSECImpl.setAlgorithm to the deployed contract\n\n### Resources\n\nhttps://github.com/ensdomains/ens-contracts-bug-62248-pr-509",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@ensdomains/ens-contracts"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "1.6.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ensdomains/ens-contracts/security/advisories/GHSA-c6rr-7pmc-73wc"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-22866"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ensdomains/ens-contracts/commit/c76c5ad0dc9de1c966443bd946fafc6351f87587"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ensdomains/ens-contracts"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ensdomains/ens-contracts-bug-62248-pr-509"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-347" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-25T18:26:58Z",
    "nvd_published_at" : "2026-02-25T16:23:25Z"
  }
}