CVE-2023-48795

What it is

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 [email protected] and (if CBC is used) the [email protected] 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, golang.org/x/crypto 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 9.5.0.0p1-Beta, WinSCP before 6.2.2, Bitvise SSH Server before 9.32, Bitvise SSH Client before 9.33, KiTTY through 0.76.1.13, 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.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of data tampering.

Exploit odds

93.5% chance of exploitation in the next 30 days (EPSS). Higher than most.

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-12-18 16:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-15 01:17 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 93.5% in the next 30 days (EPSS).
• Severity: 5.9 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-12-18 16:15 UTC

Last modified

2026-10-15 01:17 UTC

Exploit probability

93.5% · EPSS, next 30 days

Weakness

CWE-354

Record status

Modified

Affected

• Openbsd OpenSSH < 9.6
• Putty < 0.80
• filezilla-project Filezilla Client < 3.66.4
• Panic Transmit 5 < 5.10.4
• Panic Nova < 11.8
• Roumenpetrov Pkixssh < 14.4
• Winscp < 6.2.2
• Bitvise Ssh Client < 9.33

Attack profile CVSS 3.1 · 5.9

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-48795.md and follow it. Check whether this project is affected by CVE-2023-48795. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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