Let's suppose that developer D created some OS code and published it under some OS license, e.g. MIT. A company C downloaded copy of the code, modified it a bit and incorporated in its own work. Suddenly it appeared that the code had unnoticed bugs in non-modified section. Does C has now legal case against D for inflicted damages, if any has place?
To quote from the MIT License:
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
Other licenses contain similar wording, but even if they don't the general principle of "caveat emptor" applies. At least in UK law, the only way C could possibly make a successful claim against D would be if the "bugs" were actually deliberately and maliciously introduced, although that would rapidly be moving from a civil case to a criminal one.