How severe is CVE-2011-4121?

CVE-2011-4121 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2011-4121 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-4121?

CVE-2011-4121 affects Ruby-lang Ruby. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2011-4121?

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

When was CVE-2011-4121 published?

CVE-2011-4121 was published on 2019-11-26 and last updated on 2026-06-16.

CVE-2011-4121

CVE-2011-4121 is a critical-severity vulnerability in Ruby-lang Ruby with a CVSS 3.x base score of 9.8. 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-326.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 3% (83rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-326
Affected product: Ruby-lang Ruby
Published: 2019-11-26
Last modified: 2026-06-16

Description

The OpenSSL extension of Ruby (Git trunk) versions after 2011-09-01 up to 2011-11-03 always generated an exponent value of '1' to be used for private RSA key generation. A remote attacker could use this flaw to bypass or corrupt integrity of services, depending on strong private RSA keys generation mechanism.

Frequently asked questions

What is CVE-2011-4121?: The OpenSSL extension of Ruby (Git trunk) versions after 2011-09-01 up to 2011-11-03 always generated an exponent value of '1' to be used for private RSA key generation. A remote attacker could use this flaw to bypass or corrupt integrity of services, depending on strong private RSA keys generation mechanism.
How severe is CVE-2011-4121?: CVE-2011-4121 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2011-4121 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (83rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-4121?: CVE-2011-4121 affects Ruby-lang Ruby. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2011-4121?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2011-4121 published?: CVE-2011-4121 was published on 2019-11-26 and last updated on 2026-06-16.

References

Affected products (1)

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

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