High severity · published May 22, 2026
CVE-2026-46727
An issue was discovered in Ruby 4 before 4.0.5
8.1
CVSS
0.5%
EPSS
No
On KEV
Description
An issue was discovered in Ruby 4 before 4.0.5. A race condition leading to a use-after-free in the pthread-based getaddrinfo timeout handler (rb_getaddrinfo in ext/socket/raddrinfo.c) allows a remote attacker who can delay DNS responses near the user-specified timeout to crash a Ruby process that calls Addrinfo.getaddrinfo(..., timeout:) or Socket.tcp(..., resolv_timeout:). Memory-corruption-based exploitation is theoretically possible. The attack could, for example, be carried out through a crafted authoritative DNS server or recursive resolver.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 41% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RU
Ruby · ruby-lang
4.0.0 before 4.0.5 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-46727
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-46727
Permissions Required
https://hackerone.com/reports/3607434
Vendor Advisory
https://www.ruby-lang.org/en/news/2026/05/20/getaddrinfo-cve-2026-46727/
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