No exploitation reportedFix available

CVE-2011-4121

Q: Is CVE-2011-4121 actively exploited?

Active exploitation of CVE-2011-4121 has not been confirmed. Its EPSS score was 2.5% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2011-4121?

CVE-2011-4121 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2019-11-26
Fixed in1.9.3
WeaknessCWE-326

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2019-11-2605:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2011-4121?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2011-4121?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Ruby

Branch	Affected	Fixed in	Source
1.x	≥ 1.8.7.334, < 1.9.3	1.9.3	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Ruby to 1.9.3

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.19.8read 2026-10-23
NVDCVSS 2.07.5read 2026-10-23
NVDweakness (CWE)CWE-326read 2026-10-23
FIRST EPSSEPSS score2.5 %2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2019-11-26
Last Modified: 2026-06-16
NVD status: Modified

Frequently asked questions

What is CVE-2011-4121?

Is CVE-2011-4121 actively exploited?

Active exploitation of CVE-2011-4121 has not been confirmed. Its EPSS score was 2.5% on 2026-10-23, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2011-4121?

CVE-2011-4121 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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