CVE-2025-26466Medium· 5.9▾ TwilightPoC availableA flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A …
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 32.5 · likelihood 7.7 · exploitation 12
A public proof-of-concept already exists for this vulnerability — see Exploit availability below.
Public exploit / PoC code seen in 1 source. Availability, not in-the-wild use.
Stakeholder-Specific Vulnerability Categorization from CISA's ADP record at CVE.org: whether exploitation is observed, whether an attack can be automated, and how much of the system is at stake.
Exploit-prediction probability, daily snapshots since Jul 30.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via NVD
40%
5 GitHub repos
40% → 41%
Last analysed / modified upstream
A flaw was found in the OpenSSH package. For each ping packet the SSH server receives, a pong packet is allocated in a memory buffer and stored in a queue of packages. It is only freed when the server/client key exchange has finished. A malicious client may keep sending such packages, leading to an uncontrolled increase in memory consumption on the server side. Consequently, the server may become unavailable, resulting in a denial of service attack.
openssh = 9.5openssh = 9.6openssh = 9.7openssh = 9.8openssh = 9.9ubuntu_linux = 24.04ubuntu_linux = 24.10debian_linux = 11.0debian_linux = 12.0debian_linux = 13.0Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Field changes observed since this record was first indexed.
Connected by shared product, vendor, weakness, or advisory.
CVE-2025-26465Medium· 6.8A vulnerability was found in OpenSSH when the VerifyHostKeyDNS option is enabled
CVE-2023-38408Critical· 9.8The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if an agent is forwarded to an attacker-controlled system
CVE-2023-25136Medium· 6.5OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling
CVE-2020-15778High· 7.4scp in OpenSSH through 8.3p1 allows command injection in the scp.c toremote function, as demonstrated by backtick characters in the destination argument
CVE-2019-6110Medium· 6.8In OpenSSH 7.9, due to accepting and displaying arbitrary stderr output from the server, a malicious server (or Man-in-The-Middle attacker) can manipulate the client output, for example to use ANSI control codes to hide additional files …
CVE-2019-6111Medium· 5.9An issue was discovered in OpenSSH 7.9