Vulnerability in AWS S2n-Quic
CVE-2026-94450
Improper validation of the Destination Connection ID length in s2n-quic 1.88.0 and earlier may allow an unauthenticated remote user to cause a denial of service by shutting down a server endpoint via a single crafted UDP datagram. Only server endpoints specifically configured to send Retry packets are affected. To remediate this issue, users should upgrade to version v1.89.0 or later.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.019 (80.2th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 80th percentile — 80.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.019 · newest: 0.019 · change: 0.000
Affected products
Weakness classification (CWE)
References
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (release-notes, patch)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (vendor-advisory)
- ff89ba41-3aa1-4d27-914a-91399e9639e5 (release-notes)
Frequently asked questions
- What is CVE-2026-94450?
- CVE-2026-94450 is a high-severity vulnerability in AWS S2n-Quic, classified under Reachable Assertion. CVSS score: 7.5/10. Published 2026-09-22.
- How severe is CVE-2026-94450?
- High severity. CVSS v3 base score is 7.5 out of 10.