Ruby (aka CRuby) before 1.8.7-p357 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table.
Conclusion & alert: CVE-2011-4815 is rated High Risk (65.4/100): CVSS High severity, with medium exploitation likelihood (EPSS 4.25%). Core evidence: EPSS rose +2.83% over the last day, indicating growing attacker interest. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-15 | 1.41% | 4.25% | +2.83% |
| 2 | 2026-06-04 | 0.95% | 1.41% | +0.46% |
| 3 | 2026-06-03 | — | 0.95% | — |
Full EPSS history (22 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.8 | 2.0 | HIGH |
|
10.0 | 6.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
gentoo
|
normal | CVE-2011-4815: 1 GLSA(s) (201412-27), 1 atom(s) (dev-lang/ruby); latest impact normal. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2011-4815 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2011-4815 |
ubuntu
|
medium | CVE-2011-4815 medium priority: Ubuntu including 3 source packages (ruby1.8, ruby1.9, ruby1.9.1), 18 status rows across 6 suites (hardy, lucid, maverick, natty, oneiric, upstream): not-affected 8, released 5, DNE 4, ignored 1. | https://ubuntu.com/security/CVE-2011-4815 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| ruby-lang | ruby | <= 1.8.7-p352 | cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7-p299 | cpe:2.3:a:ruby-lang:ruby:1.8.7-p299:*:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7-p302 | cpe:2.3:a:ruby-lang:ruby:1.8.7-p302:*:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7-p330 | cpe:2.3:a:ruby-lang:ruby:1.8.7-p330:*:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7-p334 | cpe:2.3:a:ruby-lang:ruby:1.8.7-p334:*:*:*:*:*:*:* |