VeraCrypt vulnerabilities

VeraCrypt 1.26.29 (FUSE-T build) on macOS sometimes allows unintended access to decrypted data. It does not terminate the FUSE-T auxiliary service (go-nfsv4) and its associated VeraCrypt core-service helper processes when a volume is dismounted. After VeraCrypt reports the volume as dismounted, the auxiliary mount continues to serve the decrypted volume image (volume.dmg) over a loopback SMB session, and the leaked processes retain an open handle to the underlying raw device.

VeraCrypt from 1.26.6 until 1.26.29, file-hosted hidden volume creation forces quick format and the FormatNoFs function in src/Common/Format.c and FormatFat function in src/Common/Fat.c use WriteFile to place raw zeroed sectors at predictable 128 MiB intervals. These writes bypass the normal EncryptDataUnits formatting path, leaving deterministic plaintext markers in an area expected to resemble random ciphertext. The markers can weaken plausible deniability during forensic inspection, although they do not disclose hidden-volume content or reduce the strength of VeraCrypt encryption.

In VeraCrypt prior to 1.26.29, non-default builds created with WOLFCRYPT=1 and WOLFCRYPT_BACKEND route SHA-256 and SHA-512 volume-header key derivation through derive_key_sha256 and derive_key_sha512 in src/Crypto/wolfCrypt.c, where the configured iterations value is discarded and wc_HKDF is used instead of PBKDF2-HMAC. Changing the PIM or iteration count therefore does not increase derivation cost, allowing an attacker with an affected container, disk image, or volume header to perform substantially cheaper offline password guesses. Official precompiled VeraCrypt binaries and normal distribution packages use the standard PBKDF2 backend and are not affected. Volumes created by an affected WOLFCRYPT=1 build require backup and recreation because corrected builds derive different keys.