CVE-2023-48795 · Terrapin
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The SSH transport protocol with certain OpenSSH extensions, found in OpenSSH before 9.6 and other products, allows remote attackers to bypass…
rank 56 = 29 + 15 + 2 + 10 + 0
rank@v1 · this cycle
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.93305 · without this subject the record ranks 27
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 5.9, from NVD · without this subject the record ranks 41
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
rose on 2025-08-04 · without this subject the record ranks 54
How much of the world it touches
NVD CPE configurations
20 products in the CPE ranges · without this subject the record ranks 46
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 56
$2.85M = $4.99M incident cost x 0.6121449559255632 exposure x 0.93305 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
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The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Proof-of-concept published · 4 public repositories, 2025-01-08.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published · 4 public repositories2025-01-08receipt
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
Affected & Fixed Versions as published
Show all 20 published ranges
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What it is stated by the CNA
Terrapin is the common name for CVE-2023-48795. 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). cve-aliases@2026-08-27
Read the rest of the CNA's description
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.
NVD's analysis a second authority
- severity
- 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
- weakness
- CWE-354
- affected versions
- openbsd openssh < 9.6; putty < 0.80; filezilla-project filezilla client < 3.66.4; and 17 more, listed in full below
- also scored by
- 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
check it yourself chiark.greenend.org.uk matt.ucc.asn.au github.com netsarang.com paramiko.org openssh.com +14 morereceipt
Dated events
Movement the material steps
This score more than doubled inside 72 hours. Both observations are in the full history below.
Show all 193 observations
193 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
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What usually comes next
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