After update to 1.294 in configure hudson page below .cvspass file edit control
there is next error message:

HTTP Status 500 -

type Exception report

message

description The server encountered an internal error () that prevented it from
fulfilling this request.

exception

javax.servlet.ServletException: java.lang.NullPointerException
org.kohsuke.stapler.Stapler.invoke(Stapler.java:448)
org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:186)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:436)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:354)
org.kohsuke.stapler.Stapler.service(Stapler.java:114)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:91)
hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:83)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
hudson.security.HudsonFilter.doFilter(HudsonFilter.java:155)

root cause

java.lang.NullPointerException
hudson.scm.CVSSCM$DescriptorImpl.doCvsPassCheck(CVSSCM.java:1124)
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:585)
org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:156)
org.kohsuke.stapler.Function.bindAndInvoke(Function.java:76)
org.kohsuke.stapler.MetaClass$1.doDispatch(MetaClass.java:73)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:436)
org.kohsuke.stapler.MetaClass$6.doDispatch(MetaClass.java:186)
org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:30)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:436)
org.kohsuke.stapler.Stapler.invoke(Stapler.java:354)
org.kohsuke.stapler.Stapler.service(Stapler.java:114)
javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:91)
hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:83)
hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:76)
hudson.security.HudsonFilter.doFilter(HudsonFilter.java:155)

note The full stack trace of the root cause is available in the Apache
Tomcat/6.0.18 logs.