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. A local user or process can therefore remount and access the decrypted volume without the passphrase, e.g., by reopening a previously accessed path (such as through a macOS Open Recent menu) or by attaching volume.dmg from the stale auxiliary mount. (The macFUSE build of VeraCrypt is not affected.)

VeraCrypt provides disk encryption with strong security based on TrueCrypt. 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. This issue is fixed in version 1.26.29.

VeraCrypt provides disk encryption with strong security based on TrueCrypt. Prior to 1.26.29, non-default builds created with WOLFCRYPT=1 and WOLFCRYPTBACKEND route SHA-256 and SHA-512 volume-header key derivation through derivekeysha256 and derivekeysha512 in src/Crypto/wolfCrypt.c, where the configured iterations value is discarded and wcHKDF 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. This issue is fixed in version 1.26.29.