Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Netty's io.netty:netty-codec-http3 package, versions 4.2.0.Final through before 4.2.15.Final, uses an unlimited default maximum header size for HTTP/3 connections when the peer does not set one. A malicious client or server can send a large number of headers over a connection, exhausting memory and causing an OutOfMemoryError that crashes the application. Upgrade to 4.2.15.Final or later; the source does not list a configuration workaround.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 7.5 | High | 3.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0028, the 20th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:16 UTC First seen by agentprime
- 31 Oct 2026, 14:16 UTC Confirmed by OSV