Cloak PBKDF2 field ignores the configured iteration count and runs only :size rounds

Summary

Use of Password Hash With Insufficient Computational Effort vulnerability in danielberkompas cloak_ecto and danielberkompas cloak allows an attacker who holds the hashed values and the configured secret to brute-force low-entropy plaintexts much faster than configured. The dump/1 callback that Cloak.Ecto.PBKDF2 (Cloak.Fields.PBKDF2 in cloak before the Ecto code moved to cloak_ecto) injects into a field module calls :pbkdf2.pbkdf2/4 with config[:size] in the iteration-count position. The :iterations setting is validated but never used. With the cloak_ecto defaults (iterations: 600_000, size: 32) each hash runs 32 PBKDF2 rounds instead of 600,000, so offline guessing of values such as email addresses costs about 18,750 times less than configured. This issue affects cloak_ecto: from 1.0.0-alpha.0 onward; cloak: from 0.7.0 before 1.0.0-alpha.0.

Timeline

1. Oct 6, 2026, 8:38 AM UTCCVE published
2. Oct 6, 2026, 11:34 AM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

3. Oct 6, 2026, 11:36 AM UTCRecord last updated

Affected versions

• cloak_ecto

  From 1.0.0-alpha.0 · fixed in *

• danielberkompas/cloak_ecto

  From a8fa1642b02f1c445a1ee8794c9095eb0921f8f3 · fixed in *

• cloak

  From 0.7.0 · fixed in 1.0.0-alpha.0

• danielberkompas/cloak

  From 8699e6417a162c39d9f0ef63511bd23d3f38d1d2 · fixed in 681c9702b7cd9afe0e5a840751ab009f550c69a9

• cloak_ectoHex

  From 1.0.0-alpha.0

• cloakHex

  From 0.7.0 · fixed in 1.0.0-alpha.0

References 5