microsoft/msquic

View on GitHub

Cross-platform, C implementation of the IETF QUIC protocol, exposed to C, C++, C# and Rust.

Stars: 4.8k
Forks: 698
Open beginner issues: 0
Indexed issues: 257
Avg merge: 2d 22h
Merged PRs (30d): 35

Dominant language: C
License: MIT
Last GitHub push: Sep 17, 2026
Latest indexed: Sep 19, 2026
Contributing guide: Contributing guide
Code of conduct: Code of conduct
Beginner labels: help wanted good first issue

Beginner friendly Everything

Open All

257 open issues indexed

0-RTT rejection after reduced initial_max_data can underflow connection flow-control accounting and emit over-limit STREAM bytes Open

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/msquic#6311 · Opened Sep 7, 2026
RegistrationClose frees a QUIC_WORKER_POOL while IsExternal workers' ExecutionContexts are still linked into the external CXPLAT_WORKER_POOL, when MsQuicLib.CustomExecutions is set Open

microsoft/msquic#6308 · 1 assignee · Opened Sep 5, 2026
[CI - FAILURE]: / AppData_WithSendArgs.Send_134 (msquictest) Open

bvt ci-failure

microsoft/msquic#6290 · 1 comment · 1 assignee · Opened Sep 1, 2026
[CI - FAILURE]: / Misc.StatelessResetKey (msquictest.exe) Open

bvt ci-failure

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/msquic#6289 · 1 comment · Opened Aug 31, 2026
[CI - FAILURE]: / Handshake_WithHandshakeArgs4.RandomLossResume_1 (msquictest.exe) Open

bvt ci-failure

microsoft/msquic#6278 · 1 comment · 1 assignee · Opened Aug 28, 2026
macOS: intermittent CONNECTION_IDLE during handshake on loopback under sustained connect load Open

help wanted OS: macOS

Difficulty 4/5 3-5 days Newbie friendliness 45/100

microsoft/msquic#6265 · Opened Aug 25, 2026
The test CredValidation.ConnectValidClientCertificate fails intermittently on Server 2025 Open

Area: Testing

microsoft/msquic#6264 · 1 assignee · Opened Aug 24, 2026
Support exclusive dynamic ports for partitioned UDP listeners with io_uring Open

Area: Platform Bug: Platform OS: Linux

microsoft/msquic#6261 · 1 assignee · Opened Aug 24, 2026
[CI - FAILURE]: / Handshake_WithConnectionPoolCreateArgs.ConnectionPoolCreate_3 (msquictest.exe) Open

bvt ci-failure

microsoft/msquic#6249 · 1 assignee · Opened Aug 21, 2026
Support Raw Public Key (RPK) as described in RFC 7250. Open

feature request help wanted

Difficulty 5/5 Over a week Newbie friendliness 45/100

microsoft/msquic#6245 · Opened Aug 21, 2026
Zero-length StreamSend leaves QUIC_STREAM_SEND_FLAG_DATA set without a flush, permanently wedging the stream Open

Area: Core

microsoft/msquic#6243 · 4 comments · 1 assignee · Opened Aug 20, 2026
[CI - FAILURE]: / Handshake_WithHandshakeArgs4.RandomLossResumeRejection_2 (msquictest.exe) Open

bvt ci-failure

microsoft/msquic#6242 · 1 assignee · Opened Aug 19, 2026
2.6.0 : Visual Studio : some warnings as errors Open

Area: Build good first issue

microsoft/msquic#6234 · 8 comments · 1 assignee · Opened Aug 14, 2026
[CI - FAILURE]: stress-Debug-linux-ubuntu-24.04-x64-quictls-SanitizeAddress (spinquic) Open

ci-failure stress

microsoft/msquic#6228 · 1 assignee · Opened Aug 13, 2026
Reliable reset should not reuse RecvMaxLength to store the reliable size Open

Area: Core

microsoft/msquic#6224 · 1 assignee · Opened Aug 11, 2026
Stream callbacks are triggered at StreamClose even when StreamStart failed synchronously Open

Area: Core

microsoft/msquic#6223 · 1 assignee · Opened Aug 11, 2026
[CI - FAILURE]: / Misc_WithAbortiveArgs.AbortiveShutdown_429 (msquictest) Open

bvt ci-failure

microsoft/msquic#6222 · 1 assignee · Opened Aug 11, 2026
Spinquic: Assert FrameCount == 0 in QuicPacketBuilderFinalize when Datagram is NULL with frames pending Open

Area: Core

microsoft/msquic#6215 · 1 comment · 1 assignee · Opened Aug 11, 2026
[CI - FAILURE]: stress-Debug-windows-windows-2022-x64-quictlsxdp-v1.4 (spinquic.exe) Open

ci-failure stress

microsoft/msquic#6206 · 2 comments · 1 assignee · Opened Aug 8, 2026
[CI - FAILURE]: stress-Debug-windows-windows-2022-x64-schannelxdp-v1.4-SanitizeAddress (spinquic.exe) Open

Area: Platform ci-failure stress

microsoft/msquic#6207 · 1 comment · 1 assignee · Opened Aug 8, 2026
Hope to support wolfSSL encryption Open

Area: Platform Area: Security feature request help wanted

Difficulty 5/5 Over a week Newbie friendliness 25/100

microsoft/msquic#6175 · 1 comment · Opened Jul 26, 2026
SIGSEGV in `QuicSendBufferFill` After Connection Start Failure Open

Area: Core

microsoft/msquic#6166 · 1 assignee · Opened Jul 20, 2026
[CI - FAILURE]: stress-Debug-windows-windows-2022-x64-quictlsxdp-v1.1 (spinquic.exe) Open

ci-failure stress

microsoft/msquic#6151 · 1 comment · 1 assignee · Opened Jul 16, 2026
[CI - FAILURE]: stress-Debug-windows-windows-2022-x64-schannelxdp-v1.1-SanitizeAddress (spinquic.exe) Open

ci-failure stress

microsoft/msquic#6152 · 1 assignee · Opened Jul 16, 2026
Add testpasses for dynamically linked OpenSSL to MsQuic CI Open

Area: Automation TLS: OpenSSL

microsoft/msquic#6146 · 1 assignee · Opened Jul 14, 2026
NULL-deref (0xc0000005) in `QuicCryptoProcessTlsCompletion` — unguarded `Connection->SourceCids.Next` walk in the HANDSHAKE_COMPLETE path races connection close during deferred custom certificate validation Open

Area: Core

microsoft/msquic#6138 · 4 comments · 1 assignee · Opened Jul 8, 2026
[CI - FAILURE]: / Handshake_WithConnectionPoolCreateArgs.ConnectionPoolCreate_5 (msquictest.exe) Open

bvt ci-failure

microsoft/msquic#6133 · 1 comment · 1 assignee · Opened Jul 6, 2026
External datagram I/O for the connection state machine Open

feature request help wanted

Difficulty 5/5 Over a week Newbie friendliness 35/100

microsoft/msquic#6132 · 2 comments · Opened Jul 5, 2026
Streams may enter an unresponsive state due to "Fragment MTU exceeded" Open

Area: Core

microsoft/msquic#6126 · 1 comment · 1 assignee · Opened Jul 2, 2026
[CI - FAILURE]: stress-Debug-linux-ubuntu-22.04-x64-openssl-SanitizeAddress (spinquic) Open

ci-failure stress

microsoft/msquic#6123 · 1 assignee · Opened Jun 30, 2026
[CI - FAILURE]: / TlsTest.HandshakeParallel (msquicplatformtest.exe) Open

bvt ci-failure

microsoft/msquic#6097 · 2 comments · 1 assignee · Opened Jun 13, 2026
Unify xdp map mode and full-access XDP in the CI. Open

Area: Testing

microsoft/msquic#6096 · 1 assignee · Opened Jun 12, 2026
Refactor MsQuic gtest setup to allow better test isolation Open

Area: Testing

microsoft/msquic#6095 · 1 assignee · Opened Jun 12, 2026
Update package publishing to publish MsQuic dynamically linked against OpenSSL Open

Area: Build Area: Packaging OS: Linux

microsoft/msquic#6094 · 1 assignee · Opened Jun 12, 2026
Update the internal pipeline to build MsQuic dynamically linking OpenSSL Open

Area: Build OS: Linux

microsoft/msquic#6093 · 1 assignee · Opened Jun 12, 2026
Race in listener stop path can double-release binding during concurrent shutdown Open

microsoft/msquic#6087 · 1 assignee · Opened Jun 11, 2026
[CI - FAILURE]: stress-Debug-linux-ubuntu-22.04-x64-quictls-SanitizeAddress (spinquic) Open

ci-failure stress

microsoft/msquic#6069 · 1 comment · 1 assignee · Opened Jun 5, 2026
[CI - FAILURE]: stress-Debug-windows-WinServerPrerelease-x64-schannel (spinquic.exe) Open

ci-failure stress

microsoft/msquic#6060 · 8 comments · 1 assignee · Opened Jun 3, 2026
[CI - FAILURE]: (spinquic) Open

ci-failure stress

microsoft/msquic#6056 · 10 comments · 1 assignee · Opened Jun 1, 2026
macOS stress CI failure (spinquic) Open

Area: Stress

microsoft/msquic#6045 · 1 assignee · Opened May 28, 2026
Bugcheck: Linux Stress job SpinQuic Open

Area: Stress

microsoft/msquic#6044 · 1 assignee · Opened May 28, 2026
[CI - FAILURE]: BVT-Debug-linux-ubuntu-22.04-x64-quictls-UseSystemOpenSSLCrypto-SanitizeAddress / TlsTest.CipherSuiteMismatch (msquicplatformtest) Open

bvt ci-failure

microsoft/msquic#6041 · 1 assignee · Opened May 28, 2026
[CI - FAILURE]: stress-Debug-macos-macos-15-x64-openssl (spinquic) Open

ci-failure stress

microsoft/msquic#6040 · 1 assignee · Opened May 27, 2026
[CI - FAILURE]: stress-Debug-linux-ubuntu-24.04-x64-openssl-SanitizeAddress (spinquic) Open

ci-failure stress

microsoft/msquic#6039 · 3 comments · 1 assignee · Opened May 27, 2026
Add tests/fuzzer for raw datapath parsing functions Open

Area: Platform Area: Security Area: Testing

Difficulty 4/5 3-5 days Newbie friendliness 55/100

microsoft/msquic#6033 · 1 comment · 1 reaction · Opened May 26, 2026
PATH_RESPONSE sent on active path instead of the path where PATH_CHALLENGE was received Open

Area: Core

Difficulty 3/5 1-2 days Newbie friendliness 72/100

microsoft/msquic#6021 · Opened May 20, 2026
RFC 5.1.2: Retire destination CID when abandoning a path Open

Difficulty 3/5 1-2 days Newbie friendliness 72/100

microsoft/msquic#6019 · Opened May 20, 2026
[CI - FAILURE]: (spinquic) Open

ci-failure stress

Difficulty 4/5 3-5 days Newbie friendliness 35/100

microsoft/msquic#6018 · 1 comment · Opened May 20, 2026
[CI - FAILURE]: / Misc_WithAbortiveArgs.AbortiveShutdown_66 (msquictest.exe) Open

bvt ci-failure

microsoft/msquic#5981 · 1 assignee · Opened May 4, 2026
MsQuic + XDP receive path on Windows is slower than expected Open

Area: Performance Area: Platform

microsoft/msquic#5980 · 1 comment · 1 assignee · Opened May 4, 2026

microsoft/msquic

Get new issues in your inbox