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Fencer Vulns
medium 4.9

CVE-2023-38698 json

.eth registrar controller can shorten the duration of registered names

published 2023-08-01 3 y ago modified 2026-09-10 1 mo ago also GHSA-rrxv-q8m4-wch3 , EUVD-2023-2350

cvss
4.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

Ethereum Name Service (ENS) is a distributed, open, and extensible naming system based on the Ethereum blockchain. According to the documentation, controllers are allowed to register new domains and extend the expiry of existing domains, but they cannot change the ownership or reduce the expiration time of existing domains. However, a preliminary analysis suggests that an attacker-controlled controller may be able to reduce the expiration time of existing domains due to an integer overflow in the renew function. The vulnerability resides `@ensdomains/ens-contracts` prior to version 0.0.22.

If successfully exploited, this vulnerability would enable attackers to force the expiration of any ENS record, ultimately allowing them to claim the affected domains for themselves. Currently, it would require a malicious DAO to exploit it. Nevertheless, any vulnerability present in the controllers could potentially render this issue exploitable in the future. An additional concern is the possibility of renewal discounts. Should ENS decide to implement a system that offers unlimited .eth domains for a fixed fee in the future, the vulnerability could become exploitable by any user due to the reduced attack cost.

Version 0.0.22 contains a patch for this issue. As long as registration cost remains linear or superlinear based on registration duration, or limited to a reasonable maximum (eg, 1 million years), this vulnerability could only be exploited by a malicious DAO. The interim workaround is thus to take no action.

Patch / fix

  • npm @ensdomains/ens-contracts 0.0.22
  • ens.domains ethereum_name_service 0.0.22

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.85% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/ensdomains/ens-contracts/security/advisories/GHSA-rrxv-q8m4-wch3 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N
GitHub 3.1 4.9 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N

Affected packages

ecosystem package affected fixed in
npm @ensdomains/ens-contracts
<0.0.22
0.0.22

Affected products

  • ensdomains ens-contracts
  • ens.domains ethereum_name_service

Classification

Weakness
  • CWE-190 Integer Overflow or Wraparound

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.