Yubico YubiKey 5.4.1 through 5.7.3 before 5.7.4 has an incorrect FIDO CTAP PIN/UV Auth Protocol Two implementation. It uses the signature length from CTAP PIN/UV Auth Protocol One, even when CTAP PIN/UV Auth Protocol Two was chosen, resulting in a partial signature verification.

In Yubico pam-u2f before 1.3.1, local privilege escalation can sometimes occur. This product implements a Pluggable Authentication Module (PAM) that can be deployed to support authentication using a YubiKey or other FIDO compliant authenticators on macOS or Linux. This software package has an issue that allows for an authentication bypass in some configurations. An attacker would require the ability to access the system as an unprivileged user. Depending on the configuration, the attacker may also need to know the user's password.

Yubico YubiKey 5 Series devices with firmware before 5.7.0 and YubiHSM 2 devices with firmware before 2.4.0 allow an ECDSA secret-key extraction attack (that requires physical access and expensive equipment) in which an electromagnetic side channel is present because of a non-constant-time modular inversion for the Extended Euclidean Algorithm, aka the EUCLEAK issue. Other uses of an Infineon cryptographic library may also be affected.

Yubico YubiKey 5 Series before 5.7.0, Security Key Series before 5.7.0, YubiKey Bio Series before 5.6.4, and YubiKey 5 FIPS before 5.7.2 have Incorrect Access Control.

Yubico ykman-gui (aka YubiKey Manager GUI) before 1.2.6 on Windows, when Edge is not used, allows privilege escalation because browser windows can open as Administrator.

Incorrect access control in Yubico OTP functionality of the YubiKey hardware tokens along with the Yubico OTP validation server. The Yubico OTP supposedly creates hardware bound second factor credentials. When a user reprograms the OTP functionality by "writing" it on a token using the Yubico Personalization Tool, they can then upload the new configuration to Yubicos OTP validation servers. NOTE: the vendor disputes this because there is no way for a YubiKey device to prevent a user from deciding that a secret value, which is imported into the device, should also be stored elsewhere

Yubico ykneo-openpgp before 1.0.10 has a typo in which an invalid PIN can be used. When first powered up, a signature will be issued even though the PIN has not been validated.

The Yubico YubiHSM YubiHSM2 library 2021.08, included in the yubihsm-shell project, does not properly validate the length of some operations including SSH signing requests, and some data operations received from a YubiHSM 2 device.

Yubico pam-u2f before 1.1.1 has a logic issue that, depending on the pam-u2f configuration and the application used, could lead to a local PIN bypass. This issue does not allow user presence (touch) or cryptographic signature verification to be bypassed, so an attacker would still need to physically possess and interact with the YubiKey or another enrolled authenticator. If pam-u2f is configured to require PIN authentication, and the application using pam-u2f allows the user to submit NULL as the PIN, pam-u2f will attempt to perform a FIDO2 authentication without PIN. If this authentication is successful, the PIN requirement is bypassed.

An issue was discovered in the _send_secure_msg() function of Yubico yubihsm-shell through 2.0.3. The function does not correctly validate the embedded length field of an authenticated message received from the device because response_msg.st.len=8 can be accepted but triggers an integer overflow, which causes CRYPTO_cbc128_decrypt (in OpenSSL) to encounter an undersized buffer and experience a segmentation fault. The yubihsm-shell project is included in the YubiHSM 2 SDK product.

An issue was discovered in the /api/connector endpoint handler in Yubico yubihsm-connector before 3.0.1 (in YubiHSM SDK before 2021.04). The handler did not validate the length of the request, which can lead to a state where yubihsm-connector becomes stuck in a loop waiting for the YubiHSM to send it data, preventing any further operations until the yubihsm-connector is restarted. An attacker can send 0, 1, or 2 bytes to trigger this.

An issue was discovered in the _send_secure_msg() function of Yubico yubihsm-shell through 2.0.3. The function does not correctly validate the embedded length field of an authenticated message received from the device. Out-of-bounds reads performed by aes_remove_padding() can crash the running process, depending on the memory layout. This could be used by an attacker to cause a client-side denial of service. The yubihsm-shell project is included in the YubiHSM 2 SDK product.

An information leak was discovered on Yubico YubiKey 5 NFC devices 5.0.0 to 5.2.6 and 5.3.0 to 5.3.1. The OTP application allows a user to set optional access codes on OTP slots. This access code is intended to prevent unauthorized changes to OTP configurations. The access code is not checked when updating NFC specific components of the OTP configurations. This may allow an attacker to access configured OTPs and passwords stored in slots that were not configured by the user to be read over NFC, despite a user having set an access code. (Users who have not set an access code, or who have not configured the OTP slots, are not impacted by this issue.)

A PIN management problem was discovered on Yubico YubiKey 5 devices 5.2.0 to 5.2.6. OpenPGP has three passwords: Admin PIN, Reset Code, and User PIN. The Reset Code is used to reset the User PIN, but it is disabled by default. A flaw in the implementation of OpenPGP sets the Reset Code to a known value upon initialization. If the retry counter for the Reset Code is set to non-zero without changing the Reset Code, this known value can be used to reset the User PIN. To set the retry counters, the Admin PIN is required.

An issue was discovered in Yubico libykpiv before 2.1.0. An attacker can trigger an incorrect free() in the ykpiv_util_generate_key() function in lib/util.c through incorrect error handling code. This could be used to cause a denial of service attack.

An issue was discovered in Yubico libykpiv before 2.1.0. lib/util.c in this library (which is included in yubico-piv-tool) does not properly check embedded length fields during device communication. A malicious PIV token can misreport the returned length fields during RSA key generation. This will cause stack memory to be copied into heap allocated memory that gets returned to the caller. The leaked memory could include PINs, passwords, key material, and other sensitive information depending on the integration. During further processing by the caller, this information could leak across trust boundaries. Note that RSA key generation is triggered by the host and cannot directly be triggered by the token.

The sync endpoint in YubiKey Validation Server before 2.40 allows remote attackers to replay an OTP. NOTE: this issue is potentially relevant to persons outside Yubico who operate a self-hosted OTP validation service with a non-default configuration such as an open sync pool; the issue does NOT affect YubiCloud.

The verify endpoint in YubiKey Validation Server before 2.40 does not check the length of SQL queries, which allows remote attackers to cause a denial of service, aka SQL injection. NOTE: this issue is potentially relevant to persons outside Yubico who operate a self-hosted OTP validation service; the issue does NOT affect YubiCloud.

Yubico PAM Module before 2.10 performed user authentication when 'use_first_pass' PAM configuration option was not used and the module was configured as 'sufficient' in the PAM configuration. A remote attacker could use this flaw to circumvent common authentication process and obtain access to the account in question by providing a NULL value (pressing Ctrl-D keyboard sequence) as the password string.

In Yubico pam-u2f 1.0.7, when configured with debug and a custom debug log file is set using debug_file, that file descriptor is not closed when a new process is spawned. This leads to the file descriptor being inherited into the child process; the child process can then read from and write to it. This can leak sensitive information and also, if written to, be used to fill the disk or plant misinformation.