Cyrus IMAP 3.0.16 Release Notes


This is a bug-fix release in the 3.0 series.

Refer to the Cyrus IMAP 3.0.0 Release Notes for important information about the 3.0 series, including upgrading instructions.

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Changes Since 3.0.15

Security fixes:

  • Fixed CVE-2021-33582: Certain user inputs are used as hash table keys during processing. A poorly chosen string hashing algorithm meant that the user could control which bucket their data was stored in, allowing a malicious user to direct many inputs to a single bucket. Each subsequent insertion to the same bucket requires a strcmp of every other entry in it. At tens of thousands of entries, each new insertion could keep the CPU busy in a strcmp loop for minutes.

    The string hashing algorithm has been replaced with a better one, and now also uses a random seed per hash table, so malicious inputs cannot be precomputed.

    Discovered by Matthew Horsfall, Fastmail

Build fixes

  • Fixed: expired test certificates caused unit test failures

  • Fixed: various warnings raised by newer compilers

Bug fixes

  • Fixed: crash when looking up entries in zero-sized hash tables

  • Fixed: deduplicated code in hash_del (thanks Дилян Палаузов)

  • Fixed Issue #3456: per-server annotations were unable to replicate