SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2017-17790

The lazy_initialize function in lib/resolv.rb in Ruby through 2.4.3 uses Kernel#open, which might allow Command Injection attacks, as demonstrated by a Resolv::Hosts::new argument beginning with a '|' character, a different vulnerability than…

CRITICAL 9.8EPSS 5.91%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (5.91%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

The lazy_initialize function in lib/resolv.rb in Ruby through 2.4.3 uses Kernel#open, which might allow Command Injection attacks, as demonstrated by a Resolv::Hosts::new argument beginning with a '|' character, a different vulnerability than CVE-2017-17405. NOTE: situations with untrusted input may be highly unlikely.

CVSS 3.0
9.8 CRITICALCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
5.91% probability · 93th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-74
Affected
ruby-lang/ruby
Source
cve@mitre.org
EPSS trend
0%5%10%27 October 2026: 5.91%27 October 202627 October 2026

EPSS 5.9% since 27 October 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.