CVE-2023-51767

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-12-24 · updated 2026-10-15

Description

OpenSSH through 10.0, when common types of DRAM are used, might allow row hammer attacks (for authentication bypass) because the integer value of authenticated in mm_answer_authpassword does not resist flips of a single bit. NOTE: this is applicable to a certain threat model of attacker-victim co-location in which the attacker has user privileges. NOTE: this is disputed by the Supplier, who states "we do not consider it to be the application's responsibility to defend against platform architectural weaknesses."

Affected products

Fedoraproject Fedora: 39
OpenSSH: all versions
Red Hat Enterprise Linux: 8.0, 9.0

References

https://access.redhat.com/security/cve/CVE-2023-51767
https://arxiv.org/abs/2309.02545
https://bugzilla.redhat.com/show_bug.cgi?id=2255850
https://github.com/openssh/openssh-portable/blob/8241b9c0529228b4b86d88b1a6076fb9f97e4a99/auth-passwd.c#L77
https://github.com/openssh/openssh-portable/blob/8241b9c0529228b4b86d88b1a6076fb9f97e4a99/monitor.c#L878
https://security.netapp.com/advisory/ntap-20240125-0006/
https://ubuntu.com/security/CVE-2023-51767
https://www.openwall.com/lists/oss-security/2025/09/22/1
http://www.openwall.com/lists/oss-security/2025/09/22/1
http://www.openwall.com/lists/oss-security/2025/09/22/2
http://www.openwall.com/lists/oss-security/2025/09/23/1
http://www.openwall.com/lists/oss-security/2025/09/23/3

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