CVE-2026-28435 Denial of service in cpp-httplib
Attackers can bypass payload size limits in cpp-httplib by sending compressed data, causing resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-28435?
CVE-2026-28435 is a high-severity denial of service vulnerability in yhirose cpp-httplib, published on 4 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-28435?
It affects 1 product.
Products include Yhirose Cpp-Httplib.
How do I fix CVE-2026-28435?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-28435 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-28435 exists.
Other vulnerabilities in yhirose cpp-httplib
- CVE-2025-66570 cpp-httplib Untrusted HTTP Header Handling: Internal Header Shadowing (REMOTE*/LOCAL*)
- CVE-2026-45372 cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection
- CVE-2026-46527 Null dereference in cpp-httplib
- CVE-2026-32627 cpp-httplib has a Silent TLS Certificate Verification Bypass on HTTPS Redirect via Proxy
- CVE-2026-22776 cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb
Sources
Also known as DEBIAN-CVE-2026-28435, GHSA-xvfx-w463-6fpp, UBUNTU-CVE-2026-28435.