Vulnerabilities
Cylons seem to be physically stronger than humans. While this is obvious with respect to Centurions, the extent to which this is also true of humanoid Cylons is unclear. In the miniseries, William Adama fought in hand-to-hand with a number two who, despite suffering from the effects of radiation, proved to be physically stronger than Adama. The number two managed to break off a metal pipe to use as a club and lift Adama off the floor with one arm. In the episode "Flesh and Bone", another number two was able to break apart a pair of metal handcuffs while under interrogation. In the first season finale, "Kobol's Last Gleaming II", a Number Six engaged Kara Thrace hand-to-hand and proved to be exceptionally fast, agile and strong. Despite these demonstrations of physical strength and dexterity, humanoid Cylons are vulnerable to most of the same things as humans. The number two who fought Adama was beaten to death with a flashlight while the number six who fought Thrace was impaled by a piece of rebar. While humanoid Cylons may be at the peak of human physical strength even perhaps exceeding it, they do not appear to be superhuman and trauma which would cause severe injury or death in a human can be expected to do the same to a Cylon. Cylon skin appears just as vulnerable to breaking as human skin, with the resulting injury bleeding just as a comparable wound would in a human.
A Cylon's psychology is sufficiently similar to that of a regular human to allow for manipulation. Admiral Cain and Kara Thrace exploited this fact whilst 'interrogating' Cylons. The experience of being killed is traumatic and can leave deep emotional damage in a Humanoid Cylon.
Cylons are highly susceptible to an ancient virus which can be transmitted by rodents but which humans have developed an immunity to, lymphocytic encephalitis. This virus was carried on a beacon left by the Thirteenth Tribe at the Lion's Head Nebula millennia ago and disrupts all organic Cylon technology including Raiders, Hybrids (which in turn disrupts Centurions) and humanoid Cylons. The humans speculate that the beacon was accidentally contaminated when someone sneezed. The Cylons believe that a critical symptom of this virus, a harmful bioelectric feedback, can be transmitted during a download and have so far prevented any Cylons infected from being downloaded into a resurrection ship. The only Cylon found to be immune is a Number Eight copy, Sharon "Athena" Agathon who had given birth to a half-human child and thus 'inherited' human antibodies from her offspring (Although it is unclear if she retained this ability after she downloaded into a new body that had not given birth).
Dr. Cottle developed a vaccine to the virus which had infected a number of humanoid Cylons on a basestar near the Lion's Head Nebula. The RNA of the vaccine broke down in the blood stream of a Cylon humanoid model by their own immune response, forcing regular injections to keep an infected Cylon healthy. The Cylons themselves have not managed to develop an antidote or vaccine to the virus.
The silica pathways of humanoid Cylons are affected by certain forms of radiation, such as that surrounding Ragnar Anchorage. It is assumed but not stated that this radiation affects all types of Cylon as the station was chosen as a refuge by Commander Adama before he learned of the existence of biomechanical models and the radiation had deleterious effects on the Number Two model they found at Ragnar Anchorage (Although he was still strong enough to engage Adama in a fight and break a metal pipe before he was killed). This also suggests that humans are not vulnerable to the effects of this radiation. In addition, plutonium is used for Baltar's Cylon Detector because its radiation affects humans and Cylons differently. The detector was dropped as a plot device early in Season 2 as the revelation of Boomer (who had been a beta test subject) as a Cylon convinced the command staff that the detector did not work (Dr. Baltar lied about Boomer's test results because he feared the consequences if she learned of her identity while alone with him).
Read more about this topic: Cylon (reimagining)