Thanks to reader nini we can post the supposed specs of the EF 40mm f/2.8 pancake and the 18-135mm STM, both expected to be announced tomorrow, Friday 8th. The specifications have been published on Japanese site digicame-info (Google translated). If I got it right, they received the specs from an anonymous source. Here they are (this is machine-translated text, I made some corrections):

• EF-S18-135mm F3.5-5.6 IS STM [see image above]

– […] new focus by (STM) stepping motor and six-group zoom
– Greatly improved performance [of] video AF
– AF achieve smooth video recording of a moving subject in combination with the EOS Kiss X6i[Rebel T4i/EOS 650D] – Adopted a single sheet and high-precision aspherical lens 1 UD lens, achieving high image quality compared with conventional models
– The first with a dynamic IS valid when shooting motion
– Stage 4 minute camera shake correction in terms of shutter speed

• EF40mm F2.8 STM specs [see image below]
  – The thinnest and lightest lens in the EF line-up
  – […] smooth and quiet AF drive [adopting a] (STM) stepping motor
  – 22.8mm Length
  – 130 grams in weight
  – […] one glass mold aspherical lens
  – 7-blade circular aperture
  – noise reduction control is [achieved] adopt[ing a] micro-step drive to the diaphragm mechanism
  – Minimum focusing distance is 0.3m
  – full-time manual focus adjustment is possible to focus one-shot AF