Netty HttpServerCodec Unbounded Queue Growth via HTTP/1.1 Pipelining
Netty (io.netty:netty-codec-http) contains an unbounded per-connection queue growth flaw in HttpServerCodec. The codec tracks the HTTP method of each still-unanswered pipelined request; the first 32 entries are bit-packed into a single long, but every additional entry is appended to methodOverflowQueue, an ArrayDeque with no size limit and no rejection path. A remote, unauthenticated attacker who pipelines HTTP/1.1 requests on a single connection while withholding reads on their own end (preventing responses from being flushed) can grow this queue without bound, causing unbounded heap growth and denial of service. Affected versions are 4.2.0.Final through 4.2.17.Final and all releases up to and including 4.1.137.Final; the issue is fixed in 4.2.18.Final and 4.1.138.Final.
CVE-2026-100656
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: osv:CVE-2026-100656
Structured affected-version data
Original package identities and version rules from this source.
[
{
"ranges": [
{
"repo": "https://github.com/netty/netty",
"type": "GIT",
"events": [
{
"introduced": "09e64d259c99be8b5b2a471a78f11e65eb82598a"
},
{
"fixed": "e0789d32c72f46fd2e7c99b6fdbbf7e2f4409e44"
}
],
"database_specific": {
"source": "DESCRIPTION",
"extracted_events": [
{
"introduced": "4.2.0.Final"
},
{
"fixed": "4.2.17.Final"
}
]
}
}
],
"versions": [
"netty-4.2.16.Final",
"netty-4.2.15.Final",
"netty-4.2.14.Final",
"netty-4.2.13.Final",
"netty-4.2.12.Final",
"netty-4.2.11.Final",
"netty-4.2.10.Final",
"netty-4.2.9.Final",
"netty-4.2.8.Final",
"netty-4.2.7.Final",
"netty-4.2.6.Final",
"netty-4.2.5.Final",
"netty-4.2.4.Final",
"netty-4.2.3.Final",
"netty-4.2.2.Final",
"netty-4.2.1.Final",
"netty-4.2.0.Final"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-100656.json"
}
}
]- Related CVEs
- CVE-2026-100656
Source reference:
/id
Publisher severity
No explicit severity was provided.
- Event
- #23955 · Revision 1
- Added to Heist Feed
- Publisher date