On 24/03/2020 20:25, Viktor Dukhovni wrote: >>> I'm guessing it is not the first. The second would an issue with a >>> particular issuer on the CA list (does Exim configure a list of CAs to >>> send to the server?), >> >> I don't think so Looks like I'm wrong, from the behaviour. It's the second of the possible places, and "i" is 129. It appears to be failing the WPACKET_sub_allocate_bytes_u16() call. %rsi before the call, which I think should be the "namelen" arg, has value 172. -- Cheers, Jeremy