While decoding BER length fields, an integer overflow could occur. This could occur while parsing untrusted inputs such as X.509 certificates. The overflow does not seem to lead to any obviously exploitable condition, but exploitation cannot be positively ruled out. Only 32-bit platforms are likely affected; to cause an overflow on 64-bit the parsed data would have to be many gigabytes.
Created botan tracking bugs for this issue:
Affects: fedora-all [bug 1400895]
Affects: epel-all [bug 1400896]