Vulnerability · Published Sep 21, 2026 · Assigned by GitHub_M
CVE-2026-61541Zapros has an Unbounded Content-Encoding decompression chain that allows denial of service
Medium 6.9
In plain English
A medium-severity resource allocation without limits in zapros from kap-sh. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | zapros | 0.14.0 | GHSA-5vjj-2r48-q622 |
| PyPI | zapros | 0.14.0 | PYSEC-2026-4181 |
Affected products (as reported)
Weakness: CWE-770 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
References
- https://github.com/kap-sh/zapros/security/advisories/GHSA-5vjj-2r48-q622 x_refsource_CONFIRM