Project: h2o

Language c++
OSS-Fuzz project link
Project repository link
Build status: Fuzzers succeeding: Build log
Build status: Code coverage succeeding: Build log
Build status: Fuzz Introspector succeeding: Build log
Fuzzer count 4
Lines of code 67695
Lines covered 10833
Code coverage 16.00%
Code coverage report Report link
Static reachability 16.72%
Fuzz Introspector report Report link (from 2025-03-27)
Fuzzer Code coverage (lines) Latest Report Comments
h2o-fuzzer-http1 18.8% (avg: 18.81%, max: 18.85%) 2025-03-27
h2o-fuzzer-http2 16.36% (avg: 16.36%, max: 16.37%) 2025-03-27
h2o-fuzzer-http3 10.84% (avg: 10.84%, max: 10.87%) 2025-03-27
h2o-fuzzer-url 7.11% (avg: 7.11%, max: 7.11%) 2025-03-27

Historical Progression

Per Fuzzer Progression

Functions of interest to fuzz

This section outlines functions that may be of interest to fuzz. They are based on ranking functions that have a lot of complexity but currently exhibit low code coverage. The complexity is calculated based on the function itself as well as the functions called by the given function, i.e. the tree of code that the function triggers.


This is only a minor amount of introspection information available for this project. Please consult the Fuzz Introspector report for more information, e.g. the introspection table of all functions in the target project available here.

Function name Function source file Accumulated cyclomatic complexity Code coverage
ptls_init_compressed_certificate /src/h2o/deps/picotls/lib/certificate_compression.c 6298 0.0%
build_compressed /src/h2o/deps/picotls/lib/certificate_compression.c 6291 0.0%
BrotliEncoderCompress /src/h2o/deps/brotli/c/enc/encode.c 6237 0.0%
compress_ /src/h2o/lib/handler/compress/brotli.c 6166 0.0%
compress_core /src/h2o/lib/handler/compress/brotli.c 6150 0.0%
BrotliEncoderCompressStream /src/h2o/deps/brotli/c/enc/encode.c 6109 0.0%
ProcessMetadata /src/h2o/deps/brotli/c/enc/encode.c 6035 0.0%
EncodeData /src/h2o/deps/brotli/c/enc/encode.c 6005 0.0%
on_send_informational_complete /src/h2o/lib/http1.c 5412 0.0%
h2o_send_redirect /src/h2o/lib/core/request.c 4939 0.0%