{"action":"Upgrade zlib to 3.0.1 or later.","affected":[{"fixed":"3.2.3","introduced":"3.2.0"},{"fixed":"3.1.2","introduced":"3.1.0"},{"fixed":"3.0.1","introduced":"0"}],"component":"zlib","cve_ids":["CVE-2026-27820"],"ecosystem":"RubyGems","epss":0.00561,"exploited":false,"fixed_versions":["3.2.3","3.1.2","3.0.1"],"ghsa_id":"GHSA-g857-hhfv-j68w","id":"tcs_01M5KEK8GKHN0HSTWVZ5B36SQF","modified_at":"2026-09-10T03:50:44.477881992Z","published_at":"2026-04-16T20:40:54Z","references":["https://osv.dev/vulnerability/GHSA-g857-hhfv-j68w","https://github.com/ruby/zlib/security/advisories/GHSA-g857-hhfv-j68w","https://nvd.nist.gov/vuln/detail/CVE-2026-27820","https://hackerone.com/reports/3467067","https://github.com/ruby/zlib","https://github.com/rubysec/ruby-advisory-db/blob/master/gems/zlib/CVE-2026-27820.yml","https://www.ruby-lang.org/en/news/2026/03/05/buffer-overflow-zlib-cve-2026-27820"],"severity":{"label":"critical","score":9.8},"sources":[{"source":"osv","source_id":"GHSA-g857-hhfv-j68w","url":"https://osv.dev/vulnerability/GHSA-g857-hhfv-j68w"}],"summary":"Buffer Overflow in Zlib::GzipReader ungetc via large input leads to memory corruption"}