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
02 Description
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
03 Exploitation and scoring
- Exploitation
- Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.
- SSVC decision
- ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
- AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 89.79% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 99.7% of scored records. A rank, not a probability.
- NVD base score
- 6.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-10-14.
- Red Hat severity
- Moderate. Red Hat's rating for its own products, not a CVSS rating.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2023-02-03 00:00Z3 YR AGO
- Last updated
- 2026-10-14 22:32Z14 DAYS AGO
- Reserved
- 2023-02-03
- Assigning CNA
- mitre
- Record state
- PUBLISHED
- Severity
- Not rated by the issuing CNA
- CNA CVSS vector
- Not published by the issuing CNA
- Weaknesses
- CWE-415Double FreeVariant
- Data version
- 5.2
- Document digest
- 788da14edc86f93657bb3b84b26f75704464a91493635fe7e4732d399eb7394e
05 Affected products
06 References
- ftp.openbsd.orghttps://ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/017_sshd.patch.sig
- www.openwall.comhttps://www.openwall.com/lists/oss-security/2023/02/02/2
- bugzilla.mindrot.orghttps://bugzilla.mindrot.org/show_bug.cgi?id=3522
- github.comhttps://github.com/openssh/openssh-portable/commit/486c4dc3b83b4b67d663fb0fa62bc24138ec3946
- jfrog.comhttps://jfrog.com/blog/openssh-pre-auth-double-free-cve-2023-25136-writeup-and-proof-of-concept/
- news.ycombinator.comhttps://news.ycombinator.com/item?id=34711565
- www.openwall.com[oss-security] 20230213 Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136)http://www.openwall.com/lists/oss-security/2023/02/13/1
- www.openwall.com[oss-security] 20230222 Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136)http://www.openwall.com/lists/oss-security/2023/02/22/1
- www.openwall.com[oss-security] 20230222 Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136)http://www.openwall.com/lists/oss-security/2023/02/22/2
- www.openwall.com[oss-security] 20230223 Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136)http://www.openwall.com/lists/oss-security/2023/02/23/3
- www.openwall.com[oss-security] 20230306 Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136)http://www.openwall.com/lists/oss-security/2023/03/06/1
- www.openwall.com[oss-security] 20230309 Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136)http://www.openwall.com/lists/oss-security/2023/03/09/2
- security.netapp.comhttps://security.netapp.com/advisory/ntap-20230309-0003/
- lists.fedoraproject.orgFEDORA-2023-1176c8b10chttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R7LKQDFZWKYHQ65TBSH2X2HJQ4V2THS3/
- lists.fedoraproject.orgFEDORA-2023-123647648ehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JGAUIXJ3TEKCRKVWFQ6GDAGQFTIIGQQP/
- security.gentoo.orgGLSA-202307-01https://security.gentoo.org/glsa/202307-01
- cert-portal.siemens.comhttps://cert-portal.siemens.com/productcert/html/ssa-398330.html
07 Fixed in
AlmaLinux 9
- openssh Fixed in 8.7p1-29.el9_2
- openssh-askpass Fixed in 8.7p1-29.el9_2
- openssh-clients Fixed in 8.7p1-29.el9_2
- openssh-keycat Fixed in 8.7p1-29.el9_2
- openssh-server Fixed in 8.7p1-29.el9_2
- pam_ssh_agent_auth Fixed in 0.10.4-5.29.el9_2
Source: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Arch Linux
- openssh Fixed in 9.2p1-1
Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.
CloudLinux 9
- openssh Fixed in 8.7p1-29.el9_2
- openssh-askpass Fixed in 8.7p1-29.el9_2
- openssh-clients Fixed in 8.7p1-29.el9_2
- openssh-keycat Fixed in 8.7p1-29.el9_2
- openssh-server Fixed in 8.7p1-29.el9_2
- pam_ssh_agent_auth Fixed in 0.10.4-5.29.el9_2
Derived from AlmaLinux 9. Partial coverage: only packages taken from AlmaLinux 9 are listed.
Source: CloudLinux errata, CloudLinux Inc. Derived from: AlmaLinux, AlmaLinux OS. Copyright (c) 2023 AlmaLinux OS. Licensed under MIT License. Received through OSV.dev. Reformatted by exploit.cc.
Debian 12
- openssh Fixed in 1:9.2p1-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 13
- openssh Fixed in 1:9.2p1-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
Debian 14
- openssh Fixed in 1:9.2p1-1
Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.
A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.