{"cve":"CVE-2019-16782","nvd":{"published":"2019-12-18T20:15:16.180","modified":"2026-06-17T02:22:47.697","status":"Modified","description":"There's a possible information leak / session hijack vulnerability in Rack (RubyGem rack). This vulnerability is patched in versions 1.6.12 and 2.0.8. Attackers may be able to find and hijack sessions by using timing attacks targeting the session id. Session ids are usually stored and indexed in a database that uses some kind of scheme for speeding up lookups of that session id. By carefully measuring the amount of time it takes to look up a session, an attacker may be able to find a valid session id and hijack the session. The session id itself may be generated randomly, but the way the session is indexed by the backing store does not use a secure comparison.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","score":5.9},"cwes":["CWE-203","CWE-208"],"references":["http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00016.html","http://www.openwall.com/lists/oss-security/2019/12/18/2","http://www.openwall.com/lists/oss-security/2019/12/18/3","http://www.openwall.com/lists/oss-security/2019/12/19/3","http://www.openwall.com/lists/oss-security/2020/04/08/1"],"products":["fedoraproject:fedora","opensuse:leap","rack:rack"],"source":"nvd","synced_at":"2026-10-19T20:59:27.069234358+00:00"},"epss":{"cve":"CVE-2019-16782","score":0.03703,"percentile":0.89742,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-hrqr-hxpp-chr3","url":"https://osv.dev/vulnerability/GHSA-hrqr-hxpp-chr3","summary":"Possible Information Leak / Session Hijack Vulnerability in Rack","modified":"2026-09-10T03:49:24.917490187Z","packages":[{"ecosystem":"RubyGems","name":"rack","purl":"pkg:gem/rack","ranges":["<1.6.12"],"fixed":["1.6.12"]},{"ecosystem":"RubyGems","name":"rack","purl":"pkg:gem/rack","ranges":[">=2.0.0 <2.0.8"],"fixed":["2.0.8"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}