{"affected":[{"defaultStatus":"unaffected","ecosystem":"cargo","packageName":"rustls","product":"rustls","source":"CNA: VulnCheck","vendor":"rustls","versions":[{"lessThan":"0.23.46","status":"affected","version":"0","versionType":"semver"},{"status":"unaffected","version":"0.23.46","versionType":"semver"}]}],"cveId":"CVE-2026-123611","cwes":["CWE-757"],"description":"rustls before 0.23.46 contains a key exchange downgrade vulnerability that allows network attackers to poison the per-server-name key-exchange group record via an unauthenticated ServerHello. Attackers can answer one connection with a ServerHello selecting X25519, causing later ClientHellos to send only classical shares and lose post-quantum confidentiality.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":6.3,"severity":"medium","source":"CNA: VulnCheck","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","version":"4.0"},{"score":3.7,"severity":"low","source":"CNA: VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"}],"modifiedAt":1794101916176,"publishedAt":1794101916176,"references":[{"source":"CNA: VulnCheck","tags":["vendor-advisory"],"url":"https://github.com/rustls/rustls/security/advisories/GHSA-w44r-93j7-qv28"},{"source":"CNA: VulnCheck","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/rustls-before-0.23.46-key-exchange-downgrade-via-unauthenticated-serverhello"}],"remediation":[],"revision":"c77f2f014e8914604ab76e320acdd49fb05561aa91b903bdb11fa6bc0c712fb4","sources":[{"modifiedAt":1794101916176,"name":"CNA: VulnCheck","retrievedAt":1794103850087,"url":"https://www.cve.org/CVERecord?id=CVE-2026-123611"}],"ssvc":null,"status":"published","title":"rustls before 0.23.46 Key Exchange Downgrade via Unauthenticated ServerHello","updatedAt":1794103850087}