"So OpenSSL has optional code to reject attempts to use weak DES keys. It, sanely, is not enabled by default; if you want it you have to compile with DEVP_CHECK_DES_KEY.
Last Thursday it was reported to the openssl-dev mailing list by Ben Kaduk that there was a defect in this optional code: it had a syntax error and didn't even compile. It had a typo of '!!' instead of '||':
if (DES_set_key_checked(&deskey, &data(ctx)->ks1)
!! DES_set_key_checked(&deskey, &data(ctx)->ks2))
This syntax error was present in the original commit: the code in the #ifdefs_ had never been compiled.
The OpenSSL response? The code... that in 11 years had never been used... for a deprecated cipher... was fixed on Saturday, retaining the #ifdefs