Ruby 2.4.0 Onigmo regparse.c parse_char_class Regular Expression input validation

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability was found in Ruby 2.4.0 (Programming Language Software). It has been classified as problematic. This affects the function parse_char_class of the file regparse.c of the component Onigmo. The manipulation as part of a Regular Expression leads to a input validation vulnerability. CWE is classifying the issue as CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. This is going to have an impact on availability.

The bug was discovered 02/20/2017. The weakness was shared 04/03/2017 (Website). The advisory is shared at This vulnerability is uniquely identified as CVE-2017-6181 since 02/21/2017. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. Technical details are known, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 42 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 111873 (Photon OS 1.0: Libxml2 / Ncurses / Openldap / Ruby PHSA-2017-0024 (deprecated)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family PhotonOS Local Security Checks and running in the context local.

A possible mitigation has been published 4 months after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (111873).





  • open-source

CPE 2.3info

CPE 2.2info


VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.4

VulDB Base Score: 5.3
VulDB Temp Score: 5.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.5
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Class: Input validation
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Status: Not defined

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EPSS Percentile: 🔍

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Current Price Estimation: 🔍


Nessus ID: 111873
Nessus Name: Photon OS 1.0: Libxml2 / Ncurses / Openldap / Ruby PHSA-2017-0024 (deprecated)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Recommended: no mitigation known
Status: 🔍

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02/20/2017 🔍
02/21/2017 +1 days 🔍
04/03/2017 +41 days 🔍
04/03/2017 +0 days 🔍
04/03/2017 +0 days 🔍
04/03/2017 +0 days 🔍
07/13/2017 +101 days 🔍
08/17/2018 +400 days 🔍
11/24/2022 +1560 days 🔍


Advisory: 13234
Status: Not defined
Confirmation: 🔍

CVE: CVE-2017-6181 (🔍)
SecurityFocus: 97304 - Ruby CVE-2017-6181 Denial of Service Vulnerability
OSVDB: - CVE-2017-6181 - Onigmo - Denial of Service Issue


Created: 04/03/2017 04:59 PM
Updated: 11/24/2022 06:28 PM
Changes: 04/03/2017 04:59 PM (70), 08/25/2020 12:46 PM (6), 11/24/2022 06:28 PM (3)
Complete: 🔍


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