putty vulnerabilities

CVE-2026-48852

PuTTY 0.71 before 0.84 has an assertion failure in ECDSA signature verification.

CVE-2026-48851

PuTTY 0.77 before 0.84 uses a copy of the PuTTY icon as a trust indication for TELNET data but the trust status is not cleared between proxy authentication and the main session.

CVE-2026-48850

PuTTY 0.72 before 0.84 has a double free in RSA KEX.

PuTTY Ed25519 Signature ecc-ssh.c eddsa_verify signature verification

A vulnerability was detected in PuTTY 0.83. Affected is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation results in improper verification of cryptographic signature. The attack may be performed from remote. The attack requires a high level of complexity. The exploitability is told to be difficult. The exploit is now public and may be used. The real existence of this vulnerability is still doubted at the moment. The patch is identified as af996b5ec27ab79bae3882071b9d6acf16044549. It is advisable to implement a patch to correct this issue. The vendor was contacted early, respond

CVE-2024-31497

In PuTTY 0.68 through 0.80 before 0.81, biased ECDSA nonce generation allows an attacker to recover a user's NIST P-521 secret key via a quick attack in approximately 60 signatures. This is especially important in a scenario where an adversary is able to read messages signed by PuTTY or Pageant. The required set of signed messages may be publicly readable because they are stored in a public Git service that supports use of SSH for commit signing, and the signatures were made by Pageant through an agent-forwarding mechanism. In other words, an adversary may already have enough signature information to compromise a victim's private key, even if

• Update to 0.78-2+deb12u2

putty - security update

putty - security update

• Update to 0.78-2+deb12u1

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 0.78-2+deb12u1

CVE-2021-36367

PuTTY through 0.75 proceeds with establishing an SSH session even if it has never sent a substantive authentication response. This makes it easier for an attacker-controlled SSH server to present a later spoofed authentication prompt (that the attacker can use to capture credential data, and use that data for purposes that are undesired by the client user).

• Update to 0.75-3

CVE-2020-14002

PuTTY 0.68 through 0.73 has an Observable Discrepancy leading to an information leak in the algorithm negotiation. This allows man-in-the-middle attackers to target initial connection attempts (where no host key for the server has been cached by the client).

• Update to 0.74-1

CVE-2019-17068

PuTTY before 0.73 mishandles the "bracketed paste mode" protection mechanism, which may allow a session to be affected by malicious clipboard content.

• Update to 0.73-1

CVE-2019-17069

PuTTY before 0.73 might allow remote SSH-1 servers to cause a denial of service by accessing freed memory locations via an SSH1_MSG_DISCONNECT message.

• Update to 0.73-1

CVE-2019-9898

Potential recycling of random numbers used in cryptography exists within PuTTY before 0.71.

• Update to 0.70-6

CVE-2019-9897

Multiple denial-of-service attacks that can be triggered by writing to the terminal exist in PuTTY versions before 0.71.

• Update to 0.70-6

CVE-2019-9895

In PuTTY versions before 0.71 on Unix, a remotely triggerable buffer overflow exists in any kind of server-to-client forwarding.

• Update to 0.70-6

CVE-2019-9894

A remotely triggerable memory overwrite in RSA key exchange in PuTTY before 0.71 can occur before host key verification.

• Update to 0.70-6

CVE-2017-6542

The ssh_agent_channel_data function in PuTTY before 0.68 allows remote attackers to have unspecified impact via a large length value in an agent protocol message and leveraging the ability to connect to the Unix-domain socket representing the forwarded agent connection, which trigger a buffer overflow.

• Update to 0.67-3

CVE-2016-2563

Stack-based buffer overflow in the SCP command-line utility in PuTTY before 0.67 and KiTTY 0.66.6.3 and earlier allows remote servers to cause a denial of service (stack memory corruption) or execute arbitrary code via a crafted SCP-SINK file-size response to an SCP download request.

• Update to 0.67-1

CVE-2015-5309

Integer overflow in the terminal emulator in PuTTY before 0.66 allows remote attackers to cause a denial of service (memory corruption) or possibly execute arbitrary code via an ECH (erase characters) escape sequence with a large parameter value, which triggers a buffer underflow.

• Update to 0.66-1

CVE-2015-2157

The (1) ssh2_load_userkey and (2) ssh2_save_userkey functions in PuTTY 0.51 through 0.63 do not properly wipe SSH-2 private keys from memory, which allows local users to obtain sensitive information by reading the memory.

• Update to 0.63-10

CVE-2011-4607

PuTTY 0.59 through 0.61 does not clear sensitive process memory when managing user replies that occur during keyboard-interactive authentication, which might allow local users to read login passwords by obtaining access to the process' memory.

• Update to 0.62-1