The parser_yyerror function in the UTF-8 parser in Ruby 2.4.1 allows attackers to cause a denial of service (invalid write or read) or possibly have unspecified other impact via a crafted Ruby script, related to the parser_tokadd_utf8 function in parse.y. NOTE: this might have security relevance as a bypass of a $SAFE protection mechanism.
Conclusion & alert: CVE-2017-11465 is rated High Risk (66.4/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.68%). Core evidence: EPSS rose +1.34% 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 | 0.34% | 1.68% | +1.34% |
| 2 | 2025-12-28 | 0.39% | 0.34% | -0.05% |
| 3 | 2025-12-27 | — | 0.39% | — |
Full EPSS history (15 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 9.8 | 3.0 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
| 7.5 | 2.0 | HIGH |
|
10.0 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
redhat
|
low | — | https://access.redhat.com/security/cve/CVE-2017-11465 |
ubuntu
|
medium | CVE-2017-11465 medium priority: Ubuntu including 3 source packages (ruby1.9.1, ruby2.0, ruby2.3), 15 status rows across 5 suites (trusty, upstream, xenial, yakkety, zesty): DNE 9, not-affected 6. | https://ubuntu.com/security/CVE-2017-11465 |
| URL | Tags |
|---|---|
| https://bugs.ruby-lang.org/issues/13742 | Issue Tracking Patch Vendor Advisory |
| https://bugs.ruby-lang.org/projects/ruby-trunk/repository/revisions/59344 | Issue Tracking Patch Vendor Advisory |