CVE-2026-28435CWE-400CWE-409

Payload size limit bypass via gzip decompression in ContentReader (streaming) allows oversized request bodies in cpp-httplib

High · published March 4, 2026

CVSS v3.1
7.5
EPSS
1%
Percentile
49.7
In the wild
Unconfirmed
What it is

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.35.0, cpp-httplib (httplib.h) does not enforce Server::set_payload_max_length() on the decompressed request body when using HandlerWithContentReader (streaming ContentReader) with Content-Encoding: gzip (or other supported encodings). A small compressed payload can expand beyond the configured payload limit and be processed by the application, enabling a payload size limit bypass and potential denial of service (CPU/memory exhaustion). This vulnerability is fixed in 0.35.0.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0
Not supplied
EPSS
0.00632 · 49.7th percentile
Weaknesses
CWE-400 · Uncontrolled Resource Consumption; CWE-409 · Improper Handling of Highly Compressed Data (Data Amplification)
Published
2026-03-04T19:36Z
EPSS history
Timeline
  • 04 MAR 19:36Z
    Payload size limit bypass via gzip decompression in ContentReader (streaming) allows oversized request bodies in cpp-httplib
    cvelistv5