dropbear vulnerabilities

mkj Dropbear S Range Check curve25519.c unpackneg signature verification

A vulnerability was determined in mkj Dropbear up to 2025.89. Impacted is the function unpackneg of the file src/curve25519.c of the component S Range Check. This manipulation causes improper verification of cryptographic signature. The attack can be initiated remotely. The attack is considered to have high complexity. The exploitability is considered difficult. The actual existence of this vulnerability is currently in question. Patch name: fdec3c90a15447bd538641d85e5a3e3ac981011d. To fix this issue, it is recommended to deploy a patch. The project maintainer explains: "Signature Malleability is not exploitable in SSH protocol. (...) [A] PoC

CVE-2025-47203

dbclient in Dropbear SSH before 2025.88 allows command injection via an untrusted hostname argument, because a shell is used.

• Update to 2022.83-1+deb12u3

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 E

• Update to 2022.83-1+deb12u1

CVE-2021-36369

An issue was discovered in Dropbear through 2020.81. Due to a non-RFC-compliant check of the available authentication methods in the client-side SSH code, it is possible for an SSH server to change the login process in its favor. This attack can bypass additional security measures such as FIDO2 tokens or SSH-Askpass. Thus, it allows an attacker to abuse a forwarded agent for logging on to another server unnoticed.

• Update to 2022.82-1

CVE-2020-36254

scp.c in Dropbear before 2020.79 mishandles the filename of . or an empty filename, a related issue to CVE-2018-20685.

• Update to 2020.79-1

CVE-2019-12953

Dropbear 2011.54 through 2018.76 has an inconsistent failure delay that may lead to revealing valid usernames, a different issue than CVE-2018-15599.

• Update to 2019.78-1

CVE-2017-2659

It was found that dropbear before version 2013.59 with GSSAPI leaks whether given username is valid or invalid. When an invalid username is given, the GSSAPI authentication failure was incorrectly counted towards the maximum allowed number of password attempts.

• Update to 2013.60-1

CVE-2018-15599

The recv_msg_userauth_request function in svr-auth.c in Dropbear through 2018.76 is prone to a user enumeration vulnerability because username validity affects how fields in SSH_MSG_USERAUTH messages are handled, a similar issue to CVE-2018-15473 in an unrelated codebase.

• Update to 2018.76-4

CVE-2017-9079

Dropbear before 2017.75 might allow local users to read certain files as root, if the file has the authorized_keys file format with a command= option. This occurs because ~/.ssh/authorized_keys is read with root privileges and symlinks are followed.

• Update to 2016.74-5

CVE-2017-9078

The server in Dropbear before 2017.75 might allow post-authentication root remote code execution because of a double free in cleanup of TCP listeners when the -a option is enabled.

• Update to 2016.74-5

CVE-2016-7409

The dbclient and server in Dropbear SSH before 2016.74, when compiled with DEBUG_TRACE, allows local users to read process memory via the -v argument, related to a failed remote ident.

• Update to 2016.74-1

CVE-2016-7408

The dbclient in Dropbear SSH before 2016.74 allows remote attackers to execute arbitrary code via a crafted (1) -m or (2) -c argument.

• Update to 2016.74-1

CVE-2016-7407

The dropbearconvert command in Dropbear SSH before 2016.74 allows attackers to execute arbitrary code via a crafted OpenSSH key file.

• Update to 2016.74-1

CVE-2016-7406

Format string vulnerability in Dropbear SSH before 2016.74 allows remote attackers to execute arbitrary code via format string specifiers in the (1) username or (2) host argument.

• Update to 2016.74-1

CVE-2016-3116

CRLF injection vulnerability in Dropbear SSH before 2016.72 allows remote authenticated users to bypass intended shell-command restrictions via crafted X11 forwarding data.

• Update to 2016.72-1

CVE-2013-4434

Dropbear SSH Server before 2013.59 generates error messages for a failed logon attempt with different time delays depending on whether the user account exists, which allows remote attackers to discover valid usernames.

• Update to 2012.55-1.4

CVE-2013-4421

The buf_decompress function in packet.c in Dropbear SSH Server before 2013.59 allows remote attackers to cause a denial of service (memory consumption) via a compressed packet that has a large size when it is decompressed.

• Update to 2012.55-1.4

CVE-2012-0920

Use-after-free vulnerability in Dropbear SSH Server 0.52 through 2012.54, when command restriction and public key authentication are enabled, allows remote authenticated users to execute arbitrary code and bypass command restrictions via multiple crafted command requests, related to "channels concurrency."

• Update to 2012.55-1

CVE-2007-1099

dbclient in Dropbear SSH client before 0.49 does not sufficiently warn the user when it detects a hostkey mismatch, which might allow remote attackers to conduct man-in-the-middle attacks.

• Update to 0.49-1

CVE-2006-1206

Matt Johnston Dropbear SSH server 0.47 and earlier, as used in embedded Linux devices and on general-purpose operating systems, allows remote attackers to cause a denial of service (connection slot exhaustion) via a large number of connection attempts that exceeds the MAX_UNAUTH_CLIENTS defined value of 30.

• Update to 0.48-1