GHSA-47m2-4cr7-mhcw
HIGHquic-go: Panic occurs when queuing undecryptable packets after handshake completion
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/quic-go/quic-go🐹github.com/quic-go/quic-goReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A misbehaving or malicious server can trigger an assertion in a quic-go client (and crash the process) by sending a premature HANDSHAKE_DONE frame during the handshake.
Impact
A misbehaving or malicious server can cause a denial-of-service (DoS) attack on the quic-go client by triggering an assertion failure, leading to a process crash. This requires no authentication and can be exploited during the handshake phase. Observed in the wild with certain server implementations (e.g. Solana's Firedancer QUIC).
Affected Versions
- All versions prior to v0.49.1 (for the 0.49 branch)
- Versions v0.50.0 to v0.54.0 (inclusive)
- Fixed in v0.49.1, v0.54.1, and v0.55.0 onward
Users are recommended to upgrade to the latest patched version in their respective maintenance branch or to v0.55.0 or later.
Details
For a regular 1-RTT handshake, QUIC uses three sets of keys to encrypt / decrypt QUIC packets:
- Initial keys (derived from a static key and the connection ID)
- Handshake keys (derived from the client's and server's key shares in the TLS handshake)
- 1-RTT keys (derived when the TLS handshake finishes)
On the client side, Initial keys are discarded when the first Handshake packet is sent. Handshake keys are discarded when the server's HANDSHAKE_DONE frame is received, as specified in section 4.9.2 of RFC 9001. Crucially, Initial keys are always dropped before Handshake keys in a standard handshake.
Due to packet reordering, it is possible to receive a packet with a higher encryption level before the key for that encryption level has been derived. For example, the server's Handshake packets (containing, among others, the TLS certificate) might arrive before the server's Initial packet (which contains the TLS ServerHello). In that case, the client queues the Handshake packets and decrypts them as soon as it has processed the ServerHello and derived Handshake keys.
After completion of the handshake, Initial and Handshake packets are not needed anymore and will be dropped. quic-go implements an assertion that no packets are queued after completion of the handshake.
A misbehaving or malicious server can trigger this assertion, and thereby cause a panic, by sending a HANDSHAKE_DONE frame before actually completing the handshake. In that case, Handshake keys would be dropped before Initial keys.
This can only happen if the server implementation is misbehaving: the server can only complete the handshake after receiving the client's TLS Finished message (which is sent in Handshake packets).
The Fix
quic-go needs to be able to handle misbehaving server implementations, including those that prematurely send a HANDSHAKE_DONE frame. We now discard Initial keys when receiving a HANDSHAKE_DONE frame, thereby correctly handling premature HANDSHAKE_DONE frames. The fix was implemented in https://github.com/quic-go/quic-go/pull/5354.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/quic-go/quic-go | all versions | 0.49.1 |
| 🐹Go | github.com/quic-go/quic-go | ≥ 0.50.0&&< 0.54.1 | 0.54.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/quic-go/quic-go. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/quic-go/quic-go to 0.49.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-47m2-4cr7-mhcw is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-47m2-4cr7-mhcw is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-47m2-4cr7-mhcw. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-47m2-4cr7-mhcw in your dependencies?
O3 detects GHSA-47m2-4cr7-mhcw across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.