CVE-2026-46727Network attack vector

Process crash via getaddrinfo timeout race

Published May 22, 2026 · Updated May 22, 2026

Use-after-free in Ruby 4.0.0 through 4.0.4 allows remote attackers to crash processes by delaying DNS replies near a timeout. The rb_getaddrinfo timeout path frees its argument and then reads arg->ai when handling the timeout, dereferencing freed memory. Reachability requires timeout: in Addrinfo.getaddrinfo or resolv_timeout: in Socket.tcp; the grounded outcome is a process crash, while memory-corruption exploitation remains theoretical.

CVSS severity8.1
High
EPSS probability0.48%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Ruby 4.0.0 through 4.0.4 allows remote attackers to crash processes by delaying DNS replies near a timeout. The rb_getaddrinfo timeout path frees its argument and then reads arg->ai when handling the timeout, dereferencing freed memory. Reachability requires timeout: in Addrinfo.getaddrinfo or resolv_timeout: in Socket.tcp; the grounded outcome is a process crash, while memory-corruption exploitation remains theoretical.

The record

CVE
CVE-2026-46727
Published
May 22, 2026
Updated
May 22, 2026
Vendor
libwww-perl
Product
Ruby
Classifications
CWE-362, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 22, 2026CVE publishedPublication date reported by the CVE source.
  2. May 22, 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=4.0.0 <4.0.5

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

libwww-perl · Rubyversion=4.0.0 <4.0.5

Published CVSS scores

8.1MITRECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
7.0SUSECVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:H
8.3SUSECVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA: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 exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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