CVE-2026-22866Public exploitNetwork attack vector

Domain claims via incomplete RSA padding validation

Published Feb 25, 2026 · Updated Feb 25, 2026

RSA signature verification flaws in ENS Labs Ltd. ENS Contracts 1.6.2 and earlier allow remote attackers to claim domains using forged DNSSEC proofs. The RSASHA256Algorithm and RSASHA1Algorithm contracts compare only the trailing hash bytes after RSA recovery instead of validating the complete PKCS#1 v1.5 padding and DigestInfo structure. Exploitation requires a DNS zone whose RSA key uses a low public exponent such as e=3; affected .cc and .name domains can be claimed on ENS without DNS ownership.

CVSS severity7.5
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

RSA signature verification flaws in ENS Labs Ltd. ENS Contracts 1.6.2 and earlier allow remote attackers to claim domains using forged DNSSEC proofs. The RSASHA256Algorithm and RSASHA1Algorithm contracts compare only the trailing hash bytes after RSA recovery instead of validating the complete PKCS#1 v1.5 padding and DigestInfo structure. Exploitation requires a DNS zone whose RSA key uses a low public exponent such as e=3; affected .cc and .name domains can be claimed on ENS without DNS ownership.

The record

CVE
CVE-2026-22866
Published
Feb 25, 2026
Updated
Feb 25, 2026
Vendor
ENS Labs Ltd.
Product
ENS Contracts
Classifications
CWE-347, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 1.6.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ENS Labs Ltd. · ENS Contractsversion=<= 1.6.2

Published CVSS scores

2.7GitHub, Inc.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
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-347Improper Verification of Cryptographic Signature
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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