ZDF
Sign inSign up

Vulnerabilities

Vulnerability · CVE-2023-48795

OpenBSD openssh Improper Validation of Integrity Check Value

Published Dec 18, 2023 · catalog updated Oct 15, 2026 · OpenBSD

Patch now

CVE-2023-48795 is in the CISA known-exploited catalog. Confirm OpenBSD against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Medium5.9
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
93.55%
Remediation
Remediation guidance
Affected products
cpe bitvise/ssh client · cpe bitvise/ssh server · cpe filezilla-project/filezilla client · cpe lancom-systems/lcos · cpe lancom-systems/lcos fx · cpe lancom-systems/lcos lx

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe bitvise/ssh clientversion unspecified
  • cpe bitvise/ssh serverversion unspecified
  • cpe filezilla-project/filezilla clientversion unspecified
  • cpe lancom-systems/lcosversion unspecified
  • cpe lancom-systems/lcos fxversion unspecified
  • cpe lancom-systems/lcos lxversion unspecified
  • cpe openbsd/opensshversion unspecified
  • cpe panic/novaversion unspecified
  • cpe panic/transmit 5version unspecified
  • cpe putty/puttyversion unspecified
  • cpe roumenpetrov/pkixsshversion unspecified
  • cpe winscp/winscpversion unspecified
  • vendor OpenBSD opensshversion unspecified

How to fix CVE-2023-48795

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2023-48795 is in the CISA known-exploited catalog. Confirm OpenBSD against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

What should an analyst verify?

CWE-354. EPSS 93.55%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Dec 18, 2023 · NIST NVD

    Detected

    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 occ

  2. Feb 5, 2025 · CISA KEV

    Known exploited

    Apply remediations or mitigations per vendor instructions or discontinue use of the product if remediation or mitigations are unavailable.

  3. Oct 15, 2026 · NIST NVD

    Updated

    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 occ

Sources

  • CVE.orgVulnerability recordCVE-2023-48795

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-48795

    30-day exploitation probability 93.5%

    first.org
  • NIST NVDVulnerability recordCVE-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

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-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

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.