How severe is CVE-2017-6181?

CVE-2017-6181 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2017-6181 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-6181?

CVE-2017-6181 affects Ruby-lang Ruby. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2017-6181?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2017-6181 published?

CVE-2017-6181 was published on 2017-04-03 and last updated on 2026-06-17.

CVE-2017-6181

CVE-2017-6181 is a high-severity vulnerability in Ruby-lang Ruby with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 4% (88th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Ruby-lang Ruby
Published: 2017-04-03
Last modified: 2026-06-17

Description

The parse_char_class function in regparse.c in the Onigmo (aka Oniguruma-mod) regular expression library, as used in Ruby 2.4.0, allows remote attackers to cause a denial of service (deep recursion and application crash) via a crafted regular expression.

Frequently asked questions

What is CVE-2017-6181?: The parse_char_class function in regparse.c in the Onigmo (aka Oniguruma-mod) regular expression library, as used in Ruby 2.4.0, allows remote attackers to cause a denial of service (deep recursion and application crash) via a crafted regular expression.
How severe is CVE-2017-6181?: CVE-2017-6181 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2017-6181 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-6181?: CVE-2017-6181 affects Ruby-lang Ruby. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2017-6181?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-6181 published?: CVE-2017-6181 was published on 2017-04-03 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:ruby-lang:ruby:2.4.0:*:*:*:*:*:*:*

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