High
Io.netty/netty-codec-http: netty: denial of service via unbounded concurrent spdy streams
Type: advisorySources: OSV
A flaw was found in Netty. SpdySessionHandler accepts an unlimited number of concurrent remote-initiated streams because localConcurrentStreams defaults to Integer.MAX_VALUE and the handler provides no API to change it. A remote peer can open a SPDY connection and send a large number of SYN_STREAM frames with FLAG_FIN=0, causing unbounded heap and direct memory allocation that can lead to JVM OutOfMemoryError and a denial of service.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2026-93488
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 4 Nov 2026, 08:05 UTC · Revision 1
Source evidence
Io.netty/netty-codec-http: netty: denial of service via unbounded concurrent spdy streams
core-osv · Original sourcePublished 18 Sept 2026, 11:47 UTC
A flaw was found in Netty. SpdySessionHandler accepts an unlimited number of concurrent remote-initiated streams because localConcurrentStreams defaults to Integer.MAX_VALUE and the handler provides no API to change it. A remote peer can open a SPDY connection and send a large number of SYN_STREAM frames with FLAG_FIN=0, causing unbounded heap and direct memory allocation that can lead to JVM OutOfMemoryError and a denial of service.
osv:CVE-2026-93488
Complete source record
{
"id": "9e374096d81da4b249a8a4fca491a5ca6aa4bc9371f6c5e58bc4f3f31941bc73",
"url": "https://osv.dev/vulnerability/CVE-2026-93488",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "Io.netty/netty-codec-http: netty: denial of service via unbounded concurrent spdy streams",
"summary": "A flaw was found in Netty. SpdySessionHandler accepts an unlimited number of concurrent remote-initiated streams because localConcurrentStreams defaults to Integer.MAX_VALUE and the handler provides no API to change it. A remote peer can open a SPDY connection and send a large number of SYN_STREAM frames with FLAG_FIN=0, causing unbounded heap and direct memory allocation that can lead to JVM OutOfMemoryError and a denial of service.",
"evidence": "osv:CVE-2026-93488",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2026-93488",
"aliases": [
"CVE-2026-93488"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/netty/netty",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "26e68a2c3935e459b374891c87760f6d6c5e2550"
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{
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},
{
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"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93488.json"
}
}
],
"modified": "2026-10-28T02:30:33.635139900Z",
"provider": "osv",
"references": [
"https://access.redhat.com/downloads/content/package-browser/",
"https://access.redhat.com/jbossnetwork/restricted/listSoftware.html",
"https://github.com/netty/netty/releases/tag/netty-4.1.138.Final",
"https://github.com/netty/netty/releases/tag/netty-4.2.18.Final",
"https://access.redhat.com/errata/RHSA-2026:69440",
"https://access.redhat.com/errata/RHSA-2026:69470",
"https://access.redhat.com/errata/RHSA-2026:70257",
"https://access.redhat.com/errata/RHSA-2026:83612",
"https://access.redhat.com/security/cve/CVE-2026-93488",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93488.json",
"https://nvd.nist.gov/vuln/detail/CVE-2026-93488",
"https://bugzilla.redhat.com/show_bug.cgi?id=2536887"
],
"provider_metadata": {
"cwe_ids": [
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],
"cna_assigner": "redhat",
"unresolved_ranges": [
{
"extracted_events": [
{
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"source": "AFFECTED_FIELD",
"strategy": "InverseAffectedRanges"
}
]
}
],
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93488.json"
}
},
"related_cves": [
{
"value": "CVE-2026-93488",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 501016,
"published_at": "2026-09-18T11:47:52.574+00:00"
}