CVE-2023-25136

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, to jump to any location in the sshd address space. One third-party report states "remote code execution is theoretically possible."

• CWE-415
• CWE-415

• http://www.openwall.com/lists/oss-security/2023/02/13/1Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/02/22/1Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/02/22/2Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/02/23/3Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/03/06/1Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/03/09/2Mailing List, Third Party Advisory
• https://bugzilla.mindrot.org/show_bug.cgi?id=3522Exploit, Issue Tracking, Third Party Advisory
• https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/017_sshd.patch.sigPatch, Vendor Advisory
• https://github.com/openssh/openssh-portable/commit/486c4dc3b83b4b67d663fb0fa62bc24138ec3946Patch, Third Party Advisory
• https://jfrog.com/blog/openssh-pre-auth-double-free-cve-2023-25136-writeup-and-proof-of-concept/Exploit, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JGAUIXJ3TEKCRKVWFQ6GDAGQFTIIGQQP/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R7LKQDFZWKYHQ65TBSH2X2HJQ4V2THS3/
• https://news.ycombinator.com/item?id=34711565Issue Tracking, Third Party Advisory
• https://security.gentoo.org/glsa/202307-01Third Party Advisory
• https://security.netapp.com/advisory/ntap-20230309-0003/Third Party Advisory
• https://www.openwall.com/lists/oss-security/2023/02/02/2Exploit, Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/02/13/1Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/02/22/1Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/02/22/2Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/02/23/3Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/03/06/1Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/03/09/2Mailing List, Third Party Advisory
• https://bugzilla.mindrot.org/show_bug.cgi?id=3522Exploit, Issue Tracking, Third Party Advisory
• https://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/017_sshd.patch.sigPatch, Vendor Advisory
• https://github.com/openssh/openssh-portable/commit/486c4dc3b83b4b67d663fb0fa62bc24138ec3946Patch, Third Party Advisory
• https://jfrog.com/blog/openssh-pre-auth-double-free-cve-2023-25136-writeup-and-proof-of-concept/Exploit, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JGAUIXJ3TEKCRKVWFQ6GDAGQFTIIGQQP/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R7LKQDFZWKYHQ65TBSH2X2HJQ4V2THS3/
• https://news.ycombinator.com/item?id=34711565Issue Tracking, Third Party Advisory
• https://security.gentoo.org/glsa/202307-01Third Party Advisory
• https://security.netapp.com/advisory/ntap-20230309-0003/Third Party Advisory
• https://www.openwall.com/lists/oss-security/2023/02/02/2Exploit, Mailing List, Third Party Advisory

Published

Feb 3, 2023

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
• PR ReviewsPentest every pull request so vulnerable code is caught before it ships to production.
• AI Penetration TestingHow AI-driven penetration testing continuously covers your attack surface.

• CVE-2023-25130Rejected reason: DO NOT USE THIS CANDIDATE NUMBER. ConsultID…
• CVE-2023-25131Use of default password vulnerability in PowerPanel Business…9.8
• CVE-2023-25132Unrestricted upload of file with dangerous type vulnerabilit…9.8
• CVE-2023-25133Improper privilege management vulnerability in default.cmd f…9.8
• CVE-2023-25134McAfee Total Protection prior to 16.0.50 may allow an advers…6.7
• CVE-2023-25135vBulletin before 5.6.9 PL1 allows an unauthenticated remote …9.8
• CVE-2023-25139sprintf in the GNU C Library (glibc) 2.37 has a buffer overf…9.8
• CVE-2023-2514Mattermost Sever fails to redact the DB username and passwor…7.5
• CVE-2023-25140A vulnerability has been identified in Parasolid V34.0 (All …7.8
• CVE-2023-25141Apache Sling JCR Base < 3.1.12 has a critical injection vuln…7.5
• CVE-2023-25143An uncontrolled search path element vulnerability in the Tre…9.8
• CVE-2023-25144An improper access control vulnerability in the Trend Micro …7.8