Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1 allows an HTTP Response Splitting attack. An attacker can inject a crafted key and value into an HTTP response for the HTTP server of WEBrick.
Conclusion & alert: CVE-2017-17742 is rated Moderate Risk (58/100): CVSS Medium severity, with high exploitation likelihood (EPSS 5.76%, 92th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. EPSS rose +4.61% 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 | 1.15% | 5.76% | +4.61% |
| 2 | 2026-03-04 | 2.34% | 1.15% | -1.19% |
| 3 | 2026-03-01 | — | 2.34% | — |
Full EPSS history (43 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 5.3 | 3.0 | MEDIUM |
|
3.9 | 1.4 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
alpine
|
— | CVE-2017-17742: 1 source package rows (ruby); 10 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 0. | https://security.alpinelinux.org/vuln/CVE-2017-17742 |
debian
|
not yet assigned | CVE-2017-17742 not yet assigned priority: Debian including 1 source packages (jruby), 4 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 4. | https://security-tracker.debian.org/tracker/CVE-2017-17742 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2017-17742 |
suse
|
low | CVE-2017-17742 severity low: SUSE including 299 source package names (2.17-17.3:libruby2_5-2_5-2.5.5-4.3.1, 2.17-17.3:ruby2.5-2.5.5-4.3.1, …), 999 product×package rows across 244 product lines (Container bci/ruby, Container suse/rmt-server, … (244 product lines)): Fixed 842, Known Affected 157. | https://www.suse.com/security/cve/CVE-2017-17742/ |
ubuntu
|
medium | CVE-2017-17742 medium priority: Ubuntu including 5 source packages (jruby, ruby1.9.1, ruby2.0, ruby2.3, ruby2.5), 85 status rows across 20 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 59, ignored 10, needs-triage 7, released 6, needed 3. | https://ubuntu.com/security/CVE-2017-17742 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| ruby-lang | ruby | >= 2.2.0, < 2.2.10 | cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* |
| ruby-lang | ruby | >= 2.3.0, < 2.3.7 | cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* |
| ruby-lang | ruby | >= 2.4.0, < 2.4.4 | cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* |
| ruby-lang | ruby | >= 2.5.0, < 2.5.1 | cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:* |
| ruby-lang | ruby | 2.6.0 | cpe:2.3:a:ruby-lang:ruby:2.6.0:preview1:*:*:*:*:*:* |
| debian | debian_linux | 7.0 | cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:* |