We were seeing this error when processing responses back from HTTP calls in camel after an upgrade from 5.5.2 –> 5.6.3 due to OWASP findings.
It seems that starting in Apache HttpClient 5.6, the library introduced transparent response decompression which automatically decodes GZIP/deflate streams but no longer strips the Content-Encoding header. Because Apache Camel's HttpProducer still checks this header and attempts a secondary uncompression via GZIPHelper, the stream is double-decoded, causing the ZipException https://github.com/spring-projects/spring-ws/issues/1754 https://issues.apache.org/jira/projects/CAMEL/issues/CAMEL-24234?filter=allissues Hope that helps David On Thu, Sep 3, 2026 at 12:35 PM Martin Lichtin via users < [email protected]> wrote: > Wanted to ask about this situation with Camel Http Component deciding to > gunzip the response (due to header Content-Encoding: gzip) when in fact > the HttpClient already did that. > Symptom is: > > java.util.zip.ZipException: Not in GZIP format > at > > java.base/java.util.zip.GZIPInputStream.readHeader(GZIPInputStream.java:176) > at > java.base/java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:79) > at > java.base/java.util.zip.GZIPInputStream.<init>(GZIPInputStream.java:91) > at > org.apache.camel.support.GZIPHelper.uncompressGzip(GZIPHelper.java:41) > at > > org.apache.camel.component.http.HttpProducer.extractResponseBody(HttpProducer.java:543) > at > > org.apache.camel.component.http.HttpProducer.populateResponse(HttpProducer.java:363) > at > > org.apache.camel.component.http.HttpProducer.lambda$process$1(HttpProducer.java:266) > at > > org.apache.camel.component.http.HttpProducer.executeMethod(HttpProducer.java:500) > at > org.apache.camel.component.http.HttpProducer.process(HttpProducer.java:253) > > Setting Exchange.SKIP_GZIP_ENCODING=true solves the issue, but it does > seem like a crude workaround. > > I've seen a discussion where Httpclient maintainers say that one should > exclusively look at HttpEntity to deduce the content encoding, not the > header. > > Camel 4.18.2, Httpclient 5.6.4 > > Thanks - Martin > >
