bcrypt password hashing in Botan before 2.1.0 does not correctly handle passwords with a length between 57 and 72 characters, which makes it easier for attackers to determine the cleartext password.

The ElGamal implementation in Botan through 2.18.1, as used in Thunderbird and other products, allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.

In Botan before 2.17.3, constant-time computations are not used for certain decoding and encoding operations (base32, base58, base64, and hex).

A side-channel issue was discovered in Botan before 2.9.0. An attacker capable of precisely measuring the time taken for ECC key generation may be able to derive information about the high bits of the secret key, as the function to derive the public point from the secret scalar uses an unblinded Montgomery ladder whose loop iteration count depends on the bitlength of the secret. This issue affects only key generation, not ECDSA signatures or ECDH key agreement.

A cryptographic cache-based side channel in the RSA implementation in Botan before 1.10.17, and 1.11.x and 2.x before 2.3.0, allows a local attacker to recover information about RSA secret keys, as demonstrated by CacheD. This occurs because an array is indexed with bits derived from a secret key.

The X509_Certificate::allowed_usage function in botan 1.11.x before 1.11.31 might allow attackers to have unspecified impact by leveraging a call with more than one Key_Usage set in the enum value.

The Curve25519 code in botan before 1.11.31, on systems without a native 128-bit integer type, might allow attackers to have unspecified impact via vectors related to undefined behavior, as demonstrated on 32-bit ARM systems compiled by Clang.

botan 1.11.x before 1.11.22 improperly handles wildcard matching against hostnames, which might allow remote attackers to have unspecified impact via a valid X.509 certificate, as demonstrated by accepting *.example.com as a match for bar.foo.example.com.

botan before 1.11.22 improperly validates certificate paths, which allows remote attackers to cause a denial of service (infinite loop and memory consumption) via a certificate with a loop in the certificate chain.

botan 1.11.x before 1.11.22 makes it easier for remote attackers to decrypt TLS ciphertext data via a padding-oracle attack against TLS CBC ciphersuites.

In Botan 1.8.0 through 1.11.33, when decoding BER data an integer overflow could occur, which would cause an incorrect length field to be computed. Some API callers may use the returned (incorrect and attacker controlled) length field in a way which later causes memory corruption or other failure.

Botan 1.11.x before 1.11.29 does not enforce TLS policy for (1) signature algorithms and (2) ECC curves, which allows remote attackers to conduct downgrade attacks via unspecified vectors.

Botan before 1.10.13 and 1.11.x before 1.11.29 do not use a constant-time algorithm to perform a modular inverse on the signature nonce k, which might allow remote attackers to obtain ECDSA secret keys via a timing side-channel attack.

Heap-based buffer overflow in the P-521 reduction function in Botan 1.11.x before 1.11.27 allows remote attackers to cause a denial of service (memory overwrite and crash) or execute arbitrary code via unspecified vectors.

Integer overflow in the PointGFp constructor in Botan before 1.10.11 and 1.11.x before 1.11.27 allows remote attackers to overwrite memory and possibly execute arbitrary code via a crafted ECC point, which triggers a heap-based buffer overflow.

The ressol function in Botan before 1.10.11 and 1.11.x before 1.11.27 allows remote attackers to cause a denial of service (infinite loop) via unspecified input to the OS2ECP function, related to a composite modulus.

Botan before 1.10.13 and 1.11.x before 1.11.22 make it easier for remote attackers to conduct million-message attacks by measuring time differences, related to decoding of PKCS#1 padding.

The BER decoder in Botan 1.10.x before 1.10.10 and 1.11.x before 1.11.19 allows remote attackers to cause a denial of service (memory consumption) via unspecified vectors, related to a length field.

The BER decoder in Botan 0.10.x before 1.10.10 and 1.11.x before 1.11.19 allows remote attackers to cause a denial of service (application crash) via an empty BIT STRING in ASN.1 data.