CVE-2023-25136

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Summary

CVECVE-2023-25136
StatePUBLISHED
Assignermitre
Source PriorityCVE Program / NVD first with legacy fallback
Published2023-02-03 06:15:09 UTC
Updated2026-05-28 18:16:28 UTC
DescriptionOpenSSH 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."

Risk And Classification

Primary CVSS: v3.1 6.5 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

EPSS: 0.883290000 probability, percentile 0.995130000 (date 2026-06-01)

Problem Types: CWE-415 | n/a | CWE-415 CWE-415 Double Free

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Fedoraproject Fedora 37 All All All
Operating System Fedoraproject Fedora 38 All All All
Hardware Netapp 500f - All All All
Operating System Netapp 500f Firmware - All All All
Hardware Netapp A250 - All All All
Operating System Netapp A250 Firmware - All All All
Hardware Netapp C250 - All All All
Operating System Netapp C250 Firmware - All All All
Application Netapp Ontap Select Deploy Administration Utility - All All All
Application Openbsd Openssh 9.1 All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Na N/a affected n/a Not specified

References

ReferenceSourceLinkTags
3522 – Crash with "free(): double free detected" with old clients af854a3a-2127-422b-91ae-364da2661108 bugzilla.mindrot.org Exploit, Issue Tracking, Third Party Advisory
oss-security - Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
oss-security - Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
upstream: Always return allocated strings from the kex filtering so · openssh/openssh-portable@486c4dc · GitHub af854a3a-2127-422b-91ae-364da2661108 github.com Patch, Third Party Advisory
oss-security - double-free vulnerability in OpenSSH server 9.1 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Exploit, Mailing List, Third Party Advisory
oss-security - Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
[SECURITY] Fedora 37 Update: openssh-8.8p1-10.fc37 - package-announce - Fedora Mailing-Lists af854a3a-2127-422b-91ae-364da2661108 lists.fedoraproject.org
oss-security - Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
CVE-2023-25136 OpenSSH Pre-Auth Double Free Writeup & PoC af854a3a-2127-422b-91ae-364da2661108 jfrog.com Exploit, Third Party Advisory
oss-security - Re: Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
CVE-2023-25136 OpenSSH Vulnerability in NetApp Products | NetApp Product Security af854a3a-2127-422b-91ae-364da2661108 security.netapp.com Third Party Advisory
ftp.openbsd.org/pub/OpenBSD/patches/7.2/common/017_sshd.patch.sig af854a3a-2127-422b-91ae-364da2661108 ftp.openbsd.org Patch, Vendor Advisory
oss-security - Re: double-free vulnerability in OpenSSH server 9.1 (CVE-2023-25136) af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Third Party Advisory
OpenSSH Pre-Auth Double Free – CVE-2023-25136 – Writeup and Proof-of-Concept | Hacker News af854a3a-2127-422b-91ae-364da2661108 news.ycombinator.com Issue Tracking, Third Party Advisory
[SECURITY] Fedora 38 Update: openssh-9.0p1-15.fc38 - package-announce - Fedora Mailing-Lists af854a3a-2127-422b-91ae-364da2661108 lists.fedoraproject.org
OpenSSH: Remote Code Execution (GLSA 202307-01) — Gentoo security af854a3a-2127-422b-91ae-364da2661108 security.gentoo.org Third Party Advisory
[SECURITY] Fedora 37 Update: openssh-8.8p1-10.fc37 - package-announce - Fedora Mailing-Lists MITRE lists.fedoraproject.org
[SECURITY] Fedora 38 Update: openssh-9.0p1-15.fc38 - package-announce - Fedora Mailing-Lists MITRE lists.fedoraproject.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Legacy QID Mappings

  • 160641 Oracle Enterprise Linux Security Update for openssh (ELSA-2023-2645)
  • 184729 Debian Security Update for openssh (CVE-2023-25136)
  • 241463 Red Hat Update for openssh (RHSA-2023:2645)
  • 283896 Fedora Security Update for openssh (FEDORA-2023-1176c8b10c)
  • 284173 Fedora Security Update for openssh (FEDORA-2023-123647648e)
  • 38888 OpenSSH server 9.1 'sshd(8)' Double-Free Vulnerability
  • 673019 EulerOS Security Update for openssh (EulerOS-SA-2023-1981)
  • 673022 EulerOS Security Update for openssh (EulerOS-SA-2023-1959)
  • 710742 Gentoo Linux OpenSSH Remote Code Execution (RCE) Vulnerability (GLSA 202307-01)
  • 905383 Common Base Linux Mariner (CBL-Mariner) Security Update for openssh (13208)
  • 905384 Common Base Linux Mariner (CBL-Mariner) Security Update for openssh (13213)
  • 941047 AlmaLinux Security Update for openssh (ALSA-2023:2645)
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