We just upgraded to 5.7.2. Didn't want to since we were stable, but were forced by your Security Advisory about Struts breakage. Now we're unstable 
In particular, the /queue REST call no longer handles concurrency limits gracefully. Formerly it returned a 3xx code and a nice message, now it throws a stack trace in the logs with status=500. Excerpt from atlassian-bamboo.log:
2015-02-04 12:24:35,777 INFO [http-bio-8085-exec-37] [AccessLogFilter] 10.140.142.252 GET http:2015-02-04 12:24:35,868 INFO [http-bio-8085-exec-45] [AccessLogFilter] bamboo POST http:Feb 04, 2015 12:24:35 PM com.sun.jersey.spi.container.ContainerResponse write
SEVERE: A message body writer for Java class com.atlassian.plugins.rest.common.Status, and Java type class com.atlassian.plugins.rest.common.Status, and MIME media type application/x-www-form-urlencoded was not found
2015-02-04 12:24:35,871 ERROR [http-bio-8085-exec-45] [ContainerResponse] A message body writer for Java class com.atlassian.plugins.rest.common.Status, and Java type class com.atlassian.plugins.rest.common.Status, and MIME media type application/x-www-form-urlencoded was not found
Feb 04, 2015 12:24:35 PM com.sun.jersey.spi.container.ContainerResponse write
SEVERE: The registered message body writers compatible with the MIME media type are:
application/x-www-form-urlencoded ->
com.sun.jersey.core.impl.provider.entity.FormProvider
com.sun.jersey.core.impl.provider.entity.FormMultivaluedMapProvider
*/* ->
com.sun.jersey.core.impl.provider.entity.FormProvider
com.sun.jersey.core.impl.provider.entity.StringProvider
com.sun.jersey.core.impl.provider.entity.ByteArrayProvider
com.sun.jersey.core.impl.provider.entity.FileProvider
com.sun.jersey.core.impl.provider.entity.InputStreamProvider
com.sun.jersey.core.impl.provider.entity.DataSourceProvider
com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider$General
com.sun.jersey.core.impl.provider.entity.ReaderProvider
com.sun.jersey.core.impl.provider.entity.DocumentProvider
com.sun.jersey.core.impl.provider.entity.StreamingOutputProvider
com.sun.jersey.core.impl.provider.entity.SourceProvider$SourceWriter
com.sun.jersey.server.impl.template.ViewableMessageBodyWriter
com.sun.jersey.json.impl.provider.entity.JSONJAXBElementProvider$General
com.sun.jersey.json.impl.provider.entity.JSONArrayProvider$General
com.sun.jersey.json.impl.provider.entity.JSONObjectProvider$General
com.sun.jersey.json.impl.provider.entity.JSONWithPaddingProvider
com.sun.jersey.core.impl.provider.entity.XMLRootElementProvider$General
com.sun.jersey.core.impl.provider.entity.XMLListElementProvider$General
com.sun.jersey.json.impl.provider.entity.JSONRootElementProvider$General
com.sun.jersey.json.impl.provider.entity.JSONListElementProvider$General
com.sun.jersey.json.impl.provider.entity.JacksonProviderProxy
2015-02-04 12:24:35,871 ERROR [http-bio-8085-exec-45] [ContainerResponse] The registered message body writers compatible with the MIME media type are:
application/x-www-form-urlencoded ->
com.sun.jersey.core.impl.provider.entity.FormProvider
com.sun.jersey.core.impl.provider.entity.FormMultivaluedMapProvider
*/* ->
com.sun.jersey.core.impl.provider.entity.FormProvider
com.sun.jersey.core.impl.provider.entity.StringProvider
com.sun.jersey.core.impl.provider.entity.ByteArrayProvider
com.sun.jersey.core.impl.provider.entity.FileProvider
com.sun.jersey.core.impl.provider.entity.InputStreamProvider
com.sun.jersey.core.impl.provider.entity.DataSourceProvider
com.sun.jersey.core.impl.provider.entity.XMLJAXBElementProvider$General
com.sun.jersey.core.impl.provider.entity.ReaderProvider
com.sun.jersey.core.impl.provider.entity.DocumentProvider
com.sun.jersey.core.impl.provider.entity.StreamingOutputProvider
com.sun.jersey.core.impl.provider.entity.SourceProvider$SourceWriter
com.sun.jersey.server.impl.template.ViewableMessageBodyWriter
com.sun.jersey.json.impl.provider.entity.JSONJAXBElementProvider$General
com.sun.jersey.json.impl.provider.entity.JSONArrayProvider$General
com.sun.jersey.json.impl.provider.entity.JSONObjectProvider$General
com.sun.jersey.json.impl.provider.entity.JSONWithPaddingProvider
com.sun.jersey.core.impl.provider.entity.XMLRootElementProvider$General
com.sun.jersey.core.impl.provider.entity.XMLListElementProvider$General
com.sun.jersey.json.impl.provider.entity.JSONRootElementProvider$General
com.sun.jersey.json.impl.provider.entity.JSONListElementProvider$General
com.sun.jersey.json.impl.provider.entity.JacksonProviderProxy
2015-02-04 12:24:35,873 ERROR [http-bio-8085-exec-45] [FiveOhOh] 500 Exception was thrown.
Please provide a fix ETA ASAP. This whole Struts issue is a mess for us: first we're made vulnerable, then we have to upgrade, now the upgrade introduces more bugs ... aaagh! This new bug is delaying an internal product release and is hard to code around since little is returned to the caller to distinguish this from another 5xx return.
Hi eng-release,
I'm sorry to see you running into this issue. Could you please let me know which version of Bamboo you were using before? That will help to identify when the regression was introduced.
Thanks,
Sten Pittet
Bamboo Product Manager