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CVE-2009-4124

31
FAUCET Score

CVE-2009-4124 describes a critical heap-based buffer overflow vulnerability in Ruby 1.9.1, specifically within the rb_str_justify function. This flaw, affecting String#ljust, String#center, and String#rjust, allows unauthenticated attackers to execute arbitrary code remotely. With a CVSS score of 10.0, it represents a severe risk with complete compromise of confidentiality, integrity, and availability. Despite its high severity, there is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
1.9.1CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.9.1:-p0:*:*:*:*:*:*
1.9.1CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.9.1:-p129:*:*:*:*:*:*
1.9.1CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.9.1:-p243:*:*:*:*:*:*
1.9.1CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.9.1:-preview_1:*:*:*:*:*:*
1.9.1CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:1.9.1:-preview_2:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 2.0

10.0HIGH

AV:N/AC:L/Au:N/C:C/I:C/A:C

Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Exploitability Score
10.0
Impact Score
10.0
CvssVersion
2.0

Exploit Intelligence

EPSS Score
3.88%
Probability of exploitation in next 30 days
EPSS Percentile
89.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0387 is in the 81st percentile among its peer group of 51,553 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

redhatCVE-2009-4124Moderate

ruby: Heap-based buffer overflow in the rb_str_justify() function

Dec 7, 2009

References

secunia.com / advisories/37660
Vendor Advisory
exchange.xforce.ibmcloud.com / vulnerabilities/54674
osvdb.org / 60880
ruby-lang.org / en/news/2009/12/07/heap-overflow-in-string
PatchVendor Advisory
securityfocus.com / bid/37278
vupen.com / english/advisories/2009/3471
Vendor Advisory