{"id":"CVE-2023-25136","title":"OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling","summary":"OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, …","severity":"medium","cvss":6.5,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H","cwe":["CWE-415"],"vendor":"openbsd","product":"openssh","affected":["openssh = 9.1","fedora = 37","fedora = 38","ontap_select_deploy_administration_utility","a250_firmware","500f_firmware","c250_firmware"],"published":"2023-02-03","updated":"2026-10-14","sourceUpdated":"2026-10-14T23:17:15.010","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2023-25136","references":[{"url":"http://www.openwall.com/lists/oss-security/2023/02/13/1","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/02/22/1","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/02/22/2","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/02/23/3","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/03/06/1","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/03/09/2","label":"cve@mitre.org"},{"url":"https://bugzilla.mindrot.org/show_bug.cgi?id=3522","label":"cve@mitre.org"},{"url":"https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/017_sshd.patch.sig","label":"cve@mitre.org"},{"url":"https://github.com/openssh/openssh-portable/commit/486c4dc3b83b4b67d663fb0fa62bc24138ec3946","label":"cve@mitre.org"},{"url":"https://jfrog.com/blog/openssh-pre-auth-double-free-cve-2023-25136-writeup-and-proof-of-concept/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JGAUIXJ3TEKCRKVWFQ6GDAGQFTIIGQQP/","label":"cve@mitre.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R7LKQDFZWKYHQ65TBSH2X2HJQ4V2THS3/","label":"cve@mitre.org"},{"url":"https://news.ycombinator.com/item?id=34711565","label":"cve@mitre.org"},{"url":"https://security.gentoo.org/glsa/202307-01","label":"cve@mitre.org"},{"url":"https://security.netapp.com/advisory/ntap-20230309-0003/","label":"cve@mitre.org"},{"url":"https://www.openwall.com/lists/oss-security/2023/02/02/2","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2023/02/13/1","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2023/02/22/1","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2023/02/22/2","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2023/02/23/3","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2023/03/06/1","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2023/03/09/2","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://bugzilla.mindrot.org/show_bug.cgi?id=3522","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/017_sshd.patch.sig","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/openssh/openssh-portable/commit/486c4dc3b83b4b67d663fb0fa62bc24138ec3946","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://jfrog.com/blog/openssh-pre-auth-double-free-cve-2023-25136-writeup-and-proof-of-concept/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JGAUIXJ3TEKCRKVWFQ6GDAGQFTIIGQQP/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R7LKQDFZWKYHQ65TBSH2X2HJQ4V2THS3/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://news.ycombinator.com/item?id=34711565","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202307-01","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20230309-0003/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.openwall.com/lists/oss-security/2023/02/02/2","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://cert-portal.siemens.com/productcert/html/ssa-398330.html","label":"0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"}],"tags":["nvd","exploit-available","cve.org"],"epss":0.89685,"epssPercentile":0.99789,"exploits":{"github":11,"githubRepos":["https://github.com/jfrog/jfrog-CVE-2023-25136-OpenSSH_Double-Free","https://github.com/ticofookfook/CVE-2023-25136","https://github.com/Christbowel/CVE-2023-25136"],"checkedAt":"2026-10-15T00:02:42.044Z"},"exploitAvailable":true,"ingestedAt":"2026-10-15T00:02:07.125Z","ssvc":{"exploitation":"poc","automatable":"no","technicalImpact":"partial","timestamp":"2024-02-27T17:36:59.947126Z"},"slug":"CVE-2023-25136","body":"## Overview\n\nOpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling. This is fixed in OpenSSH 9.2. The double free can be leveraged, by an unauthenticated remote attacker in the default configuration, to jump to any location in the sshd address space. One third-party report states \"remote code execution is theoretically possible.\"\n\n## Affected\n\n- `openssh = 9.1`\n- `fedora = 37`\n- `fedora = 38`\n- `ontap_select_deploy_administration_utility`\n- `a250_firmware`\n- `500f_firmware`\n- `c250_firmware`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":66,"depthScoreParts":{"impact":35.8,"likelihood":17.9,"exploitation":12,"ransomware":0},"changes":[]}