CVSS v3
7.5
HIGH
EPSS Score
0.4 %
exploit probability, as of 2026-09-28
CISA KEV
No
known exploited
Exploitation
—
SSVC status
Description
Netty's HTTP/3 codec (io.netty:netty-codec-http3) from 4.2.0.Final through 4.2.17.Final retains unbounded per-stream QPACK encoder state. QpackEncoder stores a queue and a dynamic-table index tracker for every encoded field section that references the QPACK dynamic table, keyed by the peer-controlled QUIC stream ID, and these entries are released only when the remote decoder sends a Section Acknowledgment or Stream Cancellation instruction — not when the HTTP/3 stream completes. There is no limi
Technical details
- CVSS v3 Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Published
- 2026-09-26
- Last Modified
- 2026-09-27
Frequently asked questions
What is CVE-2026-100660?
Netty's HTTP/3 codec (io.netty:netty-codec-http3) from 4.2.0.Final through 4.2.17.Final retains unbounded per-stream QPACK encoder state. QpackEncoder stores a queue and a dynamic-table index tracker for every encoded field section that references the QPACK dynamic table, keyed by the peer-controlled QUIC stream ID, and these entries are released only when the remote decoder sends a Section Acknowledgment or Stream Cancellation instruction — not when the HTTP/3 stream completes. There is no limi
Is CVE-2026-100660 actively exploited?
Active exploitation of CVE-2026-100660 has not been confirmed. Its EPSS score was 0.4% on 2026-09-28, the estimated probability of exploitation in the next 30 days.
What is the CVSS score for CVE-2026-100660?
CVE-2026-100660 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Is CVE-2026-100660 affecting your environment?
Use isMalicious to check if any of your IPs or domains are associated with this vulnerability's IOCs.
No credit card required · 500 free checks/month · Free API key
Other 2026 vulnerabilities worth triaging
Ranked by exploit probability (EPSS).
- CVE-2026-10520KEV
- CVE-2026-24061KEV
- CVE-2026-1281KEV
- CVE-2026-1340KEVUnauthenticated Remote Code Execution via Code Injection in Ivanti Endpoint Manager Mobile
- CVE-2026-41940KEV
- CVE-2026-23760KEVSmarterTools SmarterMail < Build 9511 Authentication Bypass via Password Reset API
- CVE-2026-21643KEVSQL Injection Vulnerability in FortiClientEMS 7.4.4 Allows Unauthenticated Remote Code Execution
- CVE-2026-20182KEV