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Public proof of conceptFix available

CVE-2023-48795

Terrapin

A public proof of concept exists; no exploitation attested.

  • Published2023-12-18
  • Fixed in26.2.1 · 25.3.2.8 · 24.3.4.15 · 23.3.4.20 · 22.3.4.27
  • WeaknessCWE-354

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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 chacha20-poly1305@openssh.com and (if CBC is used) the -etm@openssh.com 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.

Timeline

dates in UTC
  1. 2023-12-1816:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-48795?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-48795?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Erlang erlang\/otp
BranchAffectedFixed in
26.x≥ 26.0, < 26.2.126.2.1
25.x≥ 25.0, < 25.3.2.825.3.2.8
24.x≥ 24.0, < 24.3.4.1524.3.4.15
23.x≥ 23.0, < 23.3.4.2023.3.4.20
22.3< 22.3.4.2722.3.4.27
Ssh
BranchAffectedFixed in
5.x≥ 5.0, < 5.1.15.1.1
4.x≥ 4.14, < 4.15.3.14.15.3.1
4.x≥ 4.12, < 4.13.2.44.13.2.4
4.x≥ 4.10, < 4.11.1.74.11.1.7
4.9< 4.9.1.54.9.1.5
Golang crypto
BranchAffectedFixed in
0.17< 0.17.00.17.0
0.x≥ 0.1.0, < 0.17.00.17.0
0.0< 0.0.0-20231218163308-9d2ee975ef9f0.0.0-20231218163308-9d2ee975ef9f

65 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • buildahAlmaLinux:9all versions · fixed in 1:1.31.4-1.el9_3and 1 other package
  • libsshAlmaLinux:8all versions · fixed in 0.9.6-13.el8_9and 2 other packages
  • opensshAlmaLinux:9all versions · fixed in 8.7p1-34.el9_3.3and 4 other packages
  • opensshAlmaLinux:8all versions · fixed in 8.0p1-19.el8_9.2and 6 other packages
  • pam_ssh_agent_authAlmaLinux:9all versions · fixed in 0.10.4-5.34.el9_3.3
  • pam_ssh_agent_authAlmaLinux:8all versions · fixed in 0.10.3-7.19.el8_9.2

Vendor advisories

  • CVE-2023-48795 Red Hat Product Security2,158 products fixed · 152 known affected

    ssh: Prefix truncation attack on Binary Packet Protocol (BPP)

    rhmtc/openshift-migration-velero-rhel8 as a component of Migration Toolkit for Containers · odo.src as a component of OpenShift Developer Tools and Services · openshift-pipelines-client.src as a component of OpenShift Pipelines · +149 more

  • RHSA-2026:79243 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Ceph Storage

  • RHSA-2026:79101 Red Hat Product Security221 products fixed

    Red Hat Security Advisory: Red Hat Ceph Storage 8.1 security and bug fix updates

  • ICSA-25-162-05 CISA5 known affected

    Siemens SIMATIC S7-1500 CPU family

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) · +2 more

  • SSA-082556 Siemens ProductCERT5 known affected

    SSA-082556: Vulnerabilities in the additional GNU/Linux subsystem of the SIMATIC S7-1500 CPU 1518(F)-4 PN/DP MFP V3.1.5

    SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) >= V3.1.5 · SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) >= V3.1.5 · SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) >= V3.1.5 · +2 more

  • RHSA-2025:4664 Red Hat Product Security42 products fixed

    Red Hat Security Advisory: Red Hat Ceph Storage 7.1 security, bug fix, and enhancement updates

71 more advisories

Full record on NVD

Fix

  1. Update Erlang erlang\/otp to 26.2.1 · 25.3.2.8 · 24.3.4.15 · 23.3.4.20 · 22.3.4.27
  2. Vendor fix Red Hat Product Security RHSA-2026:79243 · 4 productsThe container images provided by this update can be downloaded from the Red Hat container registry at registry.redhat.io using the "podman pull" command.
  3. Vendor fix Red Hat Product Security RHSA-2026:79101 · 221 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 For supported configurations, refer to: https://access.redhat.com/articles/1548993
  4. Vendor fix CISA ICSA-25-044-09 · 19 productsUpdate to V3.0.0 or later version
  5. Vendor fix Siemens ProductCERT SSA-769027 · 19 productsUpdate to V3.0.0 or later version
  6. Vendor fix Siemens ProductCERT SSA-915275 · 1 productUpdate to V1.0 SP2 Update 3 or later version
  7. Vendor fix CISA ICSA-24-319-08 · 1 productUpdate to V1.0 SP2 Update 3 or later version

Advisories and patches

Detection

read 2026-10-23 19:23 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
4 repositories, unverifiedTrixSec/CVE-2023-48795hav0cx0/CVE-2023-48795oseasfr/Scanner_CVE_OpenSSHMr-Whiskerss/SSH-Terrapin-Prefix-Truncation-Weakness-CVE-2023-48795-Checker
PoC-in-GitHub

Sources

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
Published
2023-12-18
Last Modified
2026-10-15
NVD status
Modified

Frequently asked questions

What is 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). The bypass occurs in chacha20-poly1305@openssh.com and (if CBC is used) the -etm@openssh.com 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.

Is CVE-2023-48795 actively exploited?

A proof-of-concept exploit exists for CVE-2023-48795, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2023-48795?

CVE-2023-48795 has a CVSS v3 base score of 5.9 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N.

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