CVE-2026-61541

Zapros has an Unbounded Content-Encoding decompression chain that allows denial of service

Published 21 Sep 2026 • Updated 21 Sep 2026

Severity: MEDIUM

Description

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.

Affected products (1)

• kap-sh zapros

Problem types

• CWE-770: Allocation of Resources Without Limits or Throttling

References (1)

• https://github.com/kap-sh/zapros/security/advisories/GHSA-5vjj-2r48-q622