The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass integrity checks such that some packets are omitted (from the extension negotiation message), and a client and server may consequently end up with a connection for which some security features have been downgraded or disabled, aka a Terrapin attack. This occurs because the SSH Binary Packet Protocol (BPP), implemented by these extensions, mishandles the handshake phase and mishandles use of sequence numbers. For example, there is an effective attack against SSH's use of ChaCha20-Poly1305 (and CBC with Encrypt-then-MAC). The bypass occurs in and (if CBC is used) the MAC algorithms. This also affects Maverick Synergy Java SSH API before 3.1.0-SNAPSHOT, Dropbear through 2022.83, Ssh before 5.1.1 in Erlang/OTP, PuTTY before 0.80, AsyncSSH before 2.14.2, before 0.17.0, libssh before 0.10.6, libssh2 through 1.11.0, Thorn Tech SFTP Gateway before 3.4.6, Tera Term before 5.1, Paramiko before 3.4.0, jsch before 0.2.15, SFTPGo before 2.5.6, Netgate pfSense Plus through 23.09.1, Netgate pfSense CE through 2.7.2, HPN-SSH through 18.2.0, ProFTPD before 1.3.8b (and before 1.3.9rc2), ORYX CycloneSSH before 2.3.4, NetSarang XShell 7 before Build 0144, CrushFTP before 10.6.0, ConnectBot SSH library before 2.2.22, Apache MINA sshd through 2.11.0, sshj through 0.37.0, TinySSH through 20230101, trilead-ssh2 6401, LANCOM LCOS and LANconfig, FileZilla before 3.66.4, Nova before 11.8, PKIX-SSH before 14.4, SecureCRT before 9.4.3, Transmit5 before 5.10.4, Win32-OpenSSH before, WinSCP before 6.2.2, Bitvise SSH Server before 9.32, Bitvise SSH Client before 9.33, KiTTY through, the net-ssh gem 7.2.0 for Ruby, the mscdex ssh2 module before 1.15.0 for Node.js, the thrussh library before 0.35.1 for Rust, and the Russh crate before 0.40.2 for Rust.
NVD Severity
Other trackers
Mailing lists
GitHub (code, issues), Aports (code, issues)


Type URI

Match rules

CPE URI Source package Min version Max version
cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:* openssh >= None < 9.6

Vulnerable and fixed packages

Source package Branch Version Maintainer Status
libssh edge-community 0.10.6-r0 Natanael Copa <> fixed
openssh 3.19-main 9.6_p1-r0 Natanael Copa <> fixed
libssh 3.19-community 0.10.6-r0 Natanael Copa <> fixed
py3-paramiko 3.19-community 3.4.0-r0 Fabian Affolter <> fixed
erlang 3.19-community 26.2.1-r0 Daniel Isaksen <> fixed
dropbear 3.19-main 2022.83-r4 Natanael Copa <> fixed
dropbear 3.18-main 2022.83-r2 Natanael Copa <> fixed
dropbear 3.17-main 2022.83-r1 Natanael Copa <> fixed
dropbear 3.16-main 2022.82-r2 Natanael Copa <> fixed
libssh2 3.19-main 1.11.0-r1 Natanael Copa <> fixed
py3-asyncssh 3.19-community 2.14.2-r0 Duncan Bellamy <> fixed
tinyssh 3.19-community 20230101-r3 Stuart Cardall <> fixed
filezilla 3.19-community 3.66.4-r0 Leonardo Arena <> fixed
pijul edge-community 1.0.0_beta8-r1 Celeste <> fixed
pijul 3.19-community 1.0.0_beta8-r0 Celeste <> fixed
libssh2 3.18-main 1.11.0-r0 Natanael Copa <> fixed
libssh2 3.17-main 1.11.0-r0 Natanael Copa <> fixed
libssh2 3.16-main 1.11.0-r0 Natanael Copa <> fixed
openssh 3.18-main 9.3_p2-r1 Natanael Copa <> fixed
openssh 3.17-main 9.1_p1-r5 Natanael Copa <> fixed
openssh 3.16-main 9.0_p1-r5 Natanael Copa <> fixed