Fuzz introspector
For issues and ideas: https://github.com/ossf/fuzz-introspector/issues
Project coverage

Table of contents

Project overview: connexion
High level conclusions
Reachability and coverage overview
Fuzzers overview
Project functions overview
Fuzzer details
Fuzzer: fuzz_query_resolving
Call tree
Fuzz blockers
Runtime coverage analysis
Files reached
Analyses and suggestions
Optimal target analysis
Remaining optimal interesting functions
All functions overview
Fuzz engine guidance
/src/fuzz_query_resolving.py
Dictionary
Fuzzer function priority
Runtime coverage analysis
Complex functions with low coverage
Files and Directories in report
Files in report
Directories in report
Metadata section
Report generation date: 2025-07-01

Project overview: connexion

High level conclusions

Reachability and coverage overview

Functions statically reachable by fuzzers
1.0%
11 / 1533
Cyclomatic complexity statically reachable by fuzzers
1.0%
36 / 5109
Runtime code coverage of functions
19.0%
295 / 1533

Warning: The number of runtime covered functions are larger than the number of reachable functions. This means that Fuzz Introspector found there are more functions covered at runtime than what is considered reachable based on the static analysis. This is a limitation in the analysis as anything covered at runtime is by definition reachable by the fuzzers.
This is likely due to a limitation in the static analysis. In this case, the count of functions covered at runtime is the true value, which means this is what should be considered "achieved" by the fuzzer.

Use the project functions table below to query all functions that were not covered at runtime.

Fuzzers overview

Fuzzer Fuzzer filename Functions Reached Functions unreached Fuzzer depth Files reached Basic blocks reached Cyclomatic complexity Details
fuzz_query_resolving /src/fuzz_query_resolving.py 28 2771 5 3 9 84 fuzz_query_resolving.py

Project functions overview

The following table shows data about each function in the project. The functions included in this table correspond to all functions that exist in the executables of the fuzzers. As such, there may be functions that are from third-party libraries.

For further technical details on the meaning of columns in the below table, please see the Glossary .

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzzer details

Fuzzer: fuzz_query_resolving

Call tree

The calltree shows the control flow of the fuzzer. This is overlaid with coverage information to display how much of the potential code a fuzzer can reach is in fact covered at runtime. In the following there is a link to a detailed calltree visualisation as well as a bitmap showing a high-level view of the calltree. For further information about these topics please see the glossary for full calltree and calltree overview

Full calltree

Call tree overview bitmap:

The distribution of callsites in terms of coloring is
Color Runtime hitcount Callsite count Percentage
red 0 47 65.2%
gold [1:9] 0 0.0%
yellow [10:29] 0 0.0%
greenyellow [30:49] 0 0.0%
lawngreen 50+ 25 34.7%
All colors 72 100

Fuzz blockers

The following nodes represent call sites where fuzz blockers occur.

Amount of callsites blocked Calltree index Parent function Callsite Largest blocked function
9 22 werkzeug.datastructures.structures.MultiDict.__init__ call site: 00022 werkzeug.datastructures.structures.CombinedMultiDict.items
8 61 ...fuzz_query_resolving.arbitrary call site: 00061 fdp.ConsumeUnicodeNoSurrogates
7 5 ...fuzz_query_resolving.fixed_params call site: 00005 werkzeug.datastructures.structures.CombinedMultiDict.__iter__
5 13 werkzeug.datastructures.structures.MultiDict.__init__ call site: 00013 werkzeug.datastructures.structures.CombinedMultiDict.lists
4 33 werkzeug.datastructures.structures.MultiDict.__init__ call site: 00033 fdp.ConsumeUnicodeNoSurrogates
4 49 ...fuzz_query_resolving.arbitrary call site: 00049 fdp.ConsumeUnicodeNoSurrogates
4 55 ...fuzz_query_resolving.arbitrary call site: 00055 fdp.ConsumeUnicodeNoSurrogates
2 39 ...fuzz_query_resolving.fixed_params call site: 00039 fdp.ConsumeUnicodeNoSurrogates
2 42 ...fuzz_query_resolving.fixed_params call site: 00042 werkzeug.datastructures.structures.MultiDict.items
1 2 ...fuzz_query_resolving.fixed_params call site: 00002 fdp.PickValueInList
1 20 werkzeug.datastructures.structures.MultiDict.lists call site: 00020 .super

Runtime coverage analysis

Covered functions
446
Functions that are reachable but not covered
21
Reachable functions
28
Percentage of reachable functions covered
25.0%
NB: The sum of covered functions and functions that are reachable but not covered need not be equal to Reachable functions . This is because the reachability analysis is an approximation and thus at runtime some functions may be covered that are not included in the reachability analysis. This is a limitation of our static analysis capabilities.
Warning: The number of covered functions are larger than the number of reachable functions. This means that there are more functions covered at runtime than are extracted using static analysis. This is likely a result of the static analysis component failing to extract the right call graph or the coverage runtime being compiled with sanitizers in code that the static analysis has not analysed. This can happen if lto/gold is not used in all places that coverage instrumentation is used.
Function name source code lines source lines hit percentage hit

Files reached

filename functions hit
/ 1
...fuzz_query_resolving 8
werkzeug.datastructures.structures 19

Analyses and suggestions

Optimal target analysis

Remaining optimal interesting functions

The following table shows a list of functions that are optimal targets. Optimal targets are identified by finding the functions that in combination, yield a high code coverage.

Func name Functions filename Arg count Args Function depth hitcount instr count bb count cyclomatic complexity Reachable functions Incoming references total cyclomatic complexity Unreached complexity
werkzeug.debug.DebuggedApplication.__call__ werkzeug.debug 3 ['N/A', 'N/A', 'N/A'] 7 0 1 6 5 171 0 566 554
werkzeug.test.Client.resolve_redirect werkzeug.test 3 ['N/A', 'N/A', 'N/A'] 8 0 3 8 6 145 10 487 377
werkzeug.formparser.FormDataParser.parse werkzeug.formparser 5 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 4 0 1 4 5 76 2 257 221
werkzeug.serving.run_simple werkzeug.serving 16 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 5 0 8 6 5 98 1 314 206
werkzeug.wrappers.response.Response.make_conditional werkzeug.wrappers.response 4 ['N/A', 'N/A', 'N/A', 'N/A'] 9 0 1 6 5 77 0 260 167
connexion.middleware.main.ConnexionMiddleware.add_api connexion.middleware.main 17 ['N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A', 'N/A'] 5 0 3 4 5 49 1 156 141
werkzeug.routing.rules.Rule._compile_builder werkzeug.routing.rules 2 ['N/A', 'N/A'] 5 0 8 8 6 46 4 155 131

Implementing fuzzers that target the above functions will improve reachability such that it becomes:

Functions statically reachable by fuzzers
12.0%
187 / 1533
Cyclomatic complexity statically reachable by fuzzers
14.0%
732 / 5109

All functions overview

If you implement fuzzers for these functions, the status of all functions in the project will be:

Func name Functions filename Args Function call depth Reached by Fuzzers Runtime reached by Fuzzers Combined reached by Fuzzers Fuzzers runtime hit Func lines hit % I Count BB Count Cyclomatic complexity Functions reached Reached by functions Accumulated cyclomatic complexity Undiscovered complexity

Fuzz engine guidance

This sections provides heuristics that can be used as input to a fuzz engine when running a given fuzz target. The current focus is on providing input that is usable by libFuzzer.

/src/fuzz_query_resolving.py

Dictionary

Use this with the libFuzzer -dict=DICT.file flag


Fuzzer function priority

Use one of these functions as input to libfuzzer with flag: -focus_function name 

-focus_function=['werkzeug.datastructures.structures.MultiDict.__init__', '...fuzz_query_resolving.arbitrary', '...fuzz_query_resolving.fixed_params']

Runtime coverage analysis

This section shows analysis of runtime coverage data.

For futher technical details on how this section is generated, please see the Glossary .

Complex functions with low coverage

Func name Function total lines Lines covered at runtime percentage covered Reached by fuzzers
parser.parse_args 251 49 19.52% ['fuzz_query_resolving']
werkzeug.http.parse_options_header 57 6 10.52% ['fuzz_query_resolving']
werkzeug.http.parse_range_header 40 0 0.0% []
werkzeug.http.dump_cookie 34 0 0.0% []
ranges.append 31 7 22.58% ['fuzz_query_resolving']
time.sleep 496 178 35.88% ['fuzz_query_resolving']
x.project_name.lower 156 47 30.12% ['fuzz_query_resolving']
out.update 72 30 41.66% ['fuzz_query_resolving']
logging.basicConfig 31 15 48.38% ['fuzz_query_resolving']
werkzeug.wsgi.LimitedStream.readinto 32 0 0.0% []
werkzeug.test.stream_encode_multipart.write_binary 41 0 0.0% []
werkzeug.test.EnvironBuilder.__init__ 63 0 0.0% []
werkzeug.test.Client.open 34 0 0.0% []
werkzeug.test.run_wsgi_app.start_response 32 8 25.0% ['fuzz_query_resolving']
tempfile.mkstemp 192 82 42.70% ['fuzz_query_resolving']
werkzeug.formparser.MultiPartParser.parse 33 0 0.0% []
o.isoformat 332 150 45.18% ['fuzz_query_resolving']
werkzeug.utils.send_file 81 0 0.0% []
werkzeug.sansio.multipart.MultipartDecoder.next_event 50 0 0.0% []
fields.append 93 20 21.50% ['fuzz_query_resolving']
files.items 128 28 21.87% ['fuzz_query_resolving']
name.replace 67 13 19.40% ['fuzz_query_resolving']
url.append 204 60 29.41% ['fuzz_query_resolving']
part.decode 164 39 23.78% ['fuzz_query_resolving']
markupsafe.escape.splitlines 182 73 40.10% ['fuzz_query_resolving']
collections.abc.Mapping.items 234 76 32.47% ['fuzz_query_resolving']
c.lower 254 59 23.22% ['fuzz_query_resolving']
d.lists 218 72 33.02% ['fuzz_query_resolving']
old.lower 209 90 43.06% ['fuzz_query_resolving']
yaml.load 47 22 46.80% ['fuzz_query_resolving']
loader.get_filename 48 17 35.41% ['fuzz_query_resolving']
extensions.setdefault 1669 444 26.60% ['fuzz_query_resolving']
python_multipart.multipart.parse_options_header 746 128 17.15% ['fuzz_query_resolving']
werkzeug.serving.WSGIRequestHandler.make_environ 35 0 0.0% []
werkzeug.serving.WSGIRequestHandler.run_wsgi.execute 40 0 0.0% []
werkzeug.serving.BaseWSGIServer.__init__ 45 0 0.0% []
info.strip 38 16 42.10% ['fuzz_query_resolving']
h.hexdigest 176 49 27.84% ['fuzz_query_resolving']
reader.open_resource 123 17 13.82% ['fuzz_query_resolving']
connexion.operations.swagger2.Swagger2Operation._transform_form 35 0 0.0% []
jsonschema.validators.extend 387 121 31.26% ['fuzz_query_resolving']
requests.get 207 71 34.29% ['fuzz_query_resolving']
jsonschema.exceptions.ValidationError 194 90 46.39% ['fuzz_query_resolving']
inflection.underscore 83 40 48.19% ['fuzz_query_resolving']
types.get 438 174 39.72% ['fuzz_query_resolving']
connexion.security.SecurityHandlerFactory.parse_security_scheme 31 0 0.0% []
request.cookies.get 108 49 45.37% ['fuzz_query_resolving']
errors.append 77 26 33.76% ['fuzz_query_resolving']
werkzeug.routing.map.MapAdapter.match 32 0 0.0% []
werkzeug.routing.matcher.StateMachineMatcher.match._match 74 0 0.0% []
werkzeug.routing.rules.Rule.__init__ 31 0 0.0% []
werkzeug.routing.rules.Rule._parse_rule 55 0 0.0% []
methods.add 55 19 34.54% ['fuzz_query_resolving']
p.lower 67 27 40.29% ['fuzz_query_resolving']
app.add_api 406 99 24.38% ['fuzz_query_resolving']

Files and Directories in report

This section shows which files and directories are considered in this report. The main reason for showing this is fuzz introspector may include more code in the reasoning than is desired. This section helps identify if too many files/directories are included, e.g. third party code, which may be irrelevant for the threat model. In the event too much is included, fuzz introspector supports a configuration file that can exclude data from the report. See the following link for more information on how to create a config file: link

Files in report

Source file Reached by Covered by
[] []
tempfile [] []
sys [] []
enum [] []
connexion.decorators.parameter [] []
yaml [] []
connexion.resolver [] []
werkzeug.wrappers.response [] []
werkzeug.sansio.request [] []
werkzeug.wrappers [] []
werkzeug.routing [] []
connexion.datastructures [] []
werkzeug.routing.converters [] []
connexion.middleware.response_validation [] []
hmac [] []
random [] []
uuid [] []
re [] []
werkzeug.datastructures.csp [] []
connexion.frameworks.starlette [] []
mimetypes [] []
urllib [] []
itertools [] []
connexion.problem [] []
termios [] []
connexion.apps.abstract [] []
werkzeug.middleware.profiler [] []
profile [] []
werkzeug.datastructures.cache_control [] []
werkzeug.datastructures.etag [] []
io [] []
werkzeug.datastructures.headers [] []
werkzeug.datastructures.mixins [] []
jinja2 [] []
keyword [] []
werkzeug.routing.matcher [] []
subprocess [] []
pprint [] []
werkzeug.datastructures.auth [] []
connexion.frameworks [] []
dataclasses [] []
shutil [] []
multiprocessing [] []
textwrap [] []
werkzeug.debug.tbtools [] []
werkzeug.datastructures.structures ['fuzz_query_resolving'] []
connexion.middleware.request_validation [] []
connexion.validators.form_data [] []
werkzeug.routing.rules [] []
connexion.__main__ [] []
werkzeug.urls [] []
httpx [] []
uvicorn [] []
code [] []
werkzeug.wrappers.request [] []
starlette [] []
connexion.apps [] []
werkzeug.routing.map [] []
werkzeug.http [] []
werkzeug.routing.exceptions [] []
functools [] []
connexion.uri_parsing [] []
werkzeug.sansio.response [] []
hashlib [] []
time [] []
werkzeug.sansio [] []
connexion.jsonifier [] []
math [] []
watchdog [] []
collections [] []
pydoc [] []
werkzeug.debug [] []
inspect [] []
werkzeug.utils [] []
connexion.middleware.lifespan [] []
connexion.utils [] []
connexion.http_facts [] []
connexion.middleware.main [] []
pathlib [] []
werkzeug.test [] []
connexion.middleware.context [] []
copy [] []
[] []
connexion.exceptions [] []
connexion.validators [] []
werkzeug.debug.console [] []
abc [] []
pstats [] []
werkzeug.sansio.http [] []
werkzeug.exceptions [] []
pkgutil [] []
connexion.json_schema [] []
a2wsgi [] []
http [] []
connexion.cli [] []
werkzeug.wsgi [] []
werkzeug.sansio.utils [] []
flask [] []
ssl [] []
socket [] []
selectors [] []
werkzeug.datastructures.accept [] []
signal [] []
threading [] []
warnings [] []
werkzeug.debug.repr [] []
argparse [] []
werkzeug.local [] []
winreg [] []
werkzeug.middleware.shared_data [] []
datetime [] []
connexion.spec [] []
werkzeug.sansio.multipart [] []
traceback [] []
fnmatch [] []
connexion [] []
getpass [] []
requests [] []
werkzeug._reloader [] []
zlib [] []
cryptography [] []
werkzeug.middleware [] []
werkzeug.datastructures.file_storage [] []
connexion.middleware.routing [] []
connexion.mock [] []
socketserver [] []
typing [] []
connexion.security [] []
posixpath [] []
operator [] []
connexion.operations.openapi [] []
ast [] []
connexion.types [] []
connexion.apps.flask [] []
inflection [] []
connexion.middleware.security [] []
werkzeug.datastructures [] []
connexion.context [] []
os [] []
connexion.frameworks.abstract [] []
werkzeug.testapp [] []
colorama [] []
base64 [] []
werkzeug [] []
connexion.operations.swagger2 [] []
werkzeug.formparser [] []
werkzeug.serving [] []
python_multipart [] []
werkzeug.middleware.lint [] []
codecs [] []
connexion.decorators [] []
connexion.validators.parameter [] []
atexit [] []
sysconfig [] []
unicodedata [] []
jsonschema [] []
secrets [] []
connexion.frameworks.flask [] []
connexion.middleware.abstract [] []
importlib [] []
connexion.operations [] []
connexion.middleware [] []
werkzeug.middleware.dispatcher [] []
contextvars [] []
atheris [] []
connexion.middleware.server_error [] []
werkzeug.datastructures.range [] []
markupsafe [] []
connexion.testing [] []
connexion.decorators.main [] []
connexion.validators.json [] []
connexion.options [] []
string [] []
connexion.middleware.swagger_ui [] []
connexion.handlers [] []
werkzeug.middleware.proxy_fix [] []
connexion.validators.abstract [] []
connexion.apps.asynchronous [] []
...fuzz_query_resolving ['fuzz_query_resolving'] []
werkzeug._internal [] []
unittest [] []
cProfile [] []
connexion.decorators.response [] []
werkzeug.user_agent [] []
linecache [] []
connexion.operations.abstract [] []
contextlib [] []
asyncio [] []
connexion.middleware.exceptions [] []
json [] []
asgiref [] []
werkzeug.middleware.http_proxy [] []
jsf [] []
connexion.lifecycle [] []
logging [] []
werkzeug.security [] []

Directories in report

Directory

Metadata section

This sections shows the raw data that is used to produce this report. This is mainly used for further processing and developer debugging.

Fuzzer Calltree file Program data file Coverage file
fuzz_query_resolving fuzzerLogFile-fuzz_query_resolving.data fuzzerLogFile-fuzz_query_resolving.data.yaml all_cov.json