QUIC has Broken TLS verificationGHSA-2r8v-p65x-3663
CRITICALGHSA-2r8v-p65x-3663 is a critical-severity (CVSS 9.1) CWE-295 vulnerability in quic. A fix is available for quic — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-2r8v-p65x-3663.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-2r8v-p65x-3663 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 388,997 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
quicReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Hex packages — download data is not available via public APIs for these ecosystems.
Description
erlang_quic is a pure Erlang QUIC implementation. Prior to version 1.4.4, the QUIC client did not authenticate the server during the TLS 1.3 handshake. The CertificateVerify signature was not checked, the certificate chain was not validated, and the hostname was not compared against the certificate, so verify was effectively a no-op on the client. A man-in-the-middle on the network path could present any certificate and impersonate any server, defeating the confidentiality and integrity of the connection. HTTP/3 uses the same client and was equally affected. Handshakes authenticated by a PSK (session resumption) are not affected, because the peer is authenticated by the PSK binder and no certificate is sent. This is fixed in 1.4.4. The client now verifies the CertificateVerify signature, validates the certificate chain against the trust store (cacerts option, the operating system store by default), and checks the hostname. Client verify now defaults to on; set verify => false to accept any certificate (for example a self-signed test server). No known workarounds are available before 1.4.4. verify => true had no effect, and inspecting the certificate after connecting does not help because without the signature check the peer is never proven to own the certificate it presents.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 💧Hex | quic | all versions | 1.4.4mix deps.update quic |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for quic, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update quic to 1.4.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-2r8v-p65x-3663 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.
Frequently Asked Questions
Is GHSA-2r8v-p65x-3663 in your dependencies?
Find it across Hex, including transitive dependencies.