Zapros, a Python HTTP client, prior to version 0.14.0 is vulnerable to denial of service when an application requests content from an untrusted server, or follows a redirect to one, because a malicious response containing an excessive number of chained "Content-Encoding" values causes Zapros to construct a deeply nested decompression chain that consumes excessive resources. Version 0.14.0 patches the vulnerability by limiting responses to five content-encoding layers and raising "DecodingError" when that limit is exceeded. As a workaround, applications can add response middleware that inspects the "Content-Encoding" header and rejects responses containing more than a safe number of encoding layers.