openssl — security advisory
Issue summary: OpenSSL QUIC stack does not enforce connection level flow control for streams. Remote peers may send more bytes as long as they fit within the stream flow control limits. Impact summary: A malicious remote peer may exploit the lack of connection flow control for streams to make the QUIC stack receive ~100MB of memory instead of 768 KiB (default flow control window size). CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: The local QUIC stack advertises two flow control limits to its remote peer: stream flow control limit and connection flow control limit. The remote peer must follow both limits when transmitting stream data. Whenever the local QUIC stack receives a stream frame, it validates that the size of the received stream frame stays within flow control limits. If either limit is exceeded (stream level or connection level), then the QUIC stack must close the connection with a flow control error. The vulnerable OpenSSL QUIC stack enforces the stream-level but not the connection-level limit. To exploit the issue, three conditions must be met: - the remote peer opens several streams - each stream must stay within the stream-level flow control limit - there must be no zero-offset byte sent on any of the streams (to prevent the vulnerable QUIC stack from consuming data). By meeting the conditions above, the remote peer may make the local stack allocate 2 x MAX_STREAMS x (stream flow control limit) bytes of memory. MAX_STREAMS defau
- Products
- openssl
- Affected versions
- 3.5.1-1, 3.5.1-1+deb13u1, 3.5.2-1, 3.5.3-1, 3.5.4-1, 3.5.4-1~deb13u1, 3.5.4-1~deb13u2, 3.5.5-1, 3.5.5-1~deb13u1, 3.5.5-1~deb13u2, 3.5.6-1~deb13u1, 3.5.6-1~deb13u2, 3.5.7-1~deb13u1, 3.5.7-1~deb13u2, 3.5.7-1~deb13u3, 3.6.0-1, 3.6.0-2, 3.6.0~~alpha1-1, 3.6.0~~beta1-1, 3.6.1-1, 3.6.1-2, 3.6.1-3, 3.6.2-1, 3.6.3-1, 3.6.4-1
- Fixed versions
- 3.5.7-1~deb13u3, 3.6.5-1
- CVEs
- CVE-2026-75804
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 28 Oct 2026, 10:34 UTC · Revision 1
Source evidence
Issue summary: OpenSSL QUIC stack does not enforce connection level flow control for streams. Remote peers may send more bytes as long as they fit within the stream flow control limits. Impact summary: A malicious remote peer may exploit the lack of connection flow control for streams to make the QUIC stack receive ~100MB of memory instead of 768 KiB (default flow control window size). CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: The local QUIC stack advertises two flow control limits to its remote peer: stream flow control limit and connection flow control limit. The remote peer must follow both limits when transmitting stream data. Whenever the local QUIC stack receives a stream frame, it validates that the size of the received stream frame stays within flow control limits. If either limit is exceeded (stream level or connection level), then the QUIC stack must close the connection with a flow control error. The vulnerable OpenSSL QUIC stack enforces the stream-level but not the connection-level limit. To exploit the issue, three conditions must be met: - the remote peer opens several streams - each stream must stay within the stream-level flow control limit - there must be no zero-offset byte sent on any of the streams (to prevent the vulnerable QUIC stack from consuming data). By meeting the conditions above, the remote peer may make the local stack allocate 2 x MAX_STREAMS x (stream flow control limit) bytes of memory. MAX_STREAMS defau
osv:DEBIAN-CVE-2026-75804
openssl
Fixed versions: 3.5.7-1~deb13u3
openssl
Fixed versions: 3.6.5-1
Complete source record
{
"id": "17f783062dc88066ed2d9a9c95997c8f1d5613b669a566ab2ba6008c5ce860c1",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-75804",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-75804",
"summary": "Issue summary: OpenSSL QUIC stack does not enforce connection level flow control for streams. Remote peers may send more bytes as long as they fit within the stream flow control limits. Impact summary: A malicious remote peer may exploit the lack of connection flow control for streams to make the QUIC stack receive ~100MB of memory instead of 768 KiB (default flow control window size). CWE: CWE-770: Allocation of Resources Without Limits or Throttling Description: The local QUIC stack advertises two flow control limits to its remote peer: stream flow control limit and connection flow control limit. The remote peer must follow both limits when transmitting stream data. Whenever the local QUIC stack receives a stream frame, it validates that the size of the received stream frame stays within flow control limits. If either limit is exceeded (stream level or connection level), then the QUIC stack must close the connection with a flow control error. The vulnerable OpenSSL QUIC stack enforces the stream-level but not the connection-level limit. To exploit the issue, three conditions must be met: - the remote peer opens several streams - each stream must stay within the stream-level flow control limit - there must be no zero-offset byte sent on any of the streams (to prevent the vulnerable QUIC stack from consuming data). By meeting the conditions above, the remote peer may make the local stack allocate 2 x MAX_STREAMS x (stream flow control limit) bytes of memory. MAX_STREAMS defau",
"evidence": "osv:DEBIAN-CVE-2026-75804",
"products": [
{
"name": {
"value": "openssl",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.5.7-1~deb13u3",
"evidence": "/affected/0/ranges"
}
],
"affected_versions": [
{
"value": "3.5.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.1-1+deb13u1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.2-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.3-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.4-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.4-1~deb13u1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.4-1~deb13u2",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.5-1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.5-1~deb13u1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.5-1~deb13u2",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.6-1~deb13u1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.6-1~deb13u2",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.7-1~deb13u1",
"evidence": "/affected/0/versions"
},
{
"value": "3.5.7-1~deb13u2",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "openssl",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "3.6.5-1",
"evidence": "/affected/1/ranges"
}
],
"affected_versions": [
{
"value": "3.5.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.4-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.4-1~deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.4-1~deb13u2",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.5-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.5-1~deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.5-1~deb13u2",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.6-1~deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.6-1~deb13u2",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.7-1~deb13u1",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.7-1~deb13u2",
"evidence": "/affected/1/versions"
},
{
"value": "3.5.7-1~deb13u3",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.0-2",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.0~~alpha1-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.0~~beta1-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.1-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.1-2",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.1-3",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.2-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.3-1",
"evidence": "/affected/1/versions"
},
{
"value": "3.6.4-1",
"evidence": "/affected/1/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "DEBIAN-CVE-2026-75804",
"aliases": [
"DEBIAN-CVE-2026-75804"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.5.7-1~deb13u3"
}
]
}
],
"package": {
"name": "openssl",
"purl": "pkg:deb/debian/openssl?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"3.5.1-1",
"3.5.1-1+deb13u1",
"3.5.2-1",
"3.5.3-1",
"3.5.4-1",
"3.5.4-1~deb13u1",
"3.5.4-1~deb13u2",
"3.5.5-1",
"3.5.5-1~deb13u1",
"3.5.5-1~deb13u2",
"3.5.6-1~deb13u1",
"3.5.6-1~deb13u2",
"3.5.7-1~deb13u1",
"3.5.7-1~deb13u2"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75804.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "3.6.5-1"
}
]
}
],
"package": {
"name": "openssl",
"purl": "pkg:deb/debian/openssl?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"3.5.1-1",
"3.5.2-1",
"3.5.3-1",
"3.5.4-1",
"3.5.4-1~deb13u1",
"3.5.4-1~deb13u2",
"3.5.5-1",
"3.5.5-1~deb13u1",
"3.5.5-1~deb13u2",
"3.5.6-1~deb13u1",
"3.5.6-1~deb13u2",
"3.5.7-1~deb13u1",
"3.5.7-1~deb13u2",
"3.5.7-1~deb13u3",
"3.6.0-1",
"3.6.0-2",
"3.6.0~~alpha1-1",
"3.6.0~~beta1-1",
"3.6.1-1",
"3.6.1-2",
"3.6.1-3",
"3.6.2-1",
"3.6.3-1",
"3.6.4-1"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-75804.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-08T23:00:11.168800152Z",
"provider": "osv",
"upstream": [
"CVE-2026-75804"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-75804"
]
},
"related_cves": [
{
"value": "CVE-2026-75804",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 107902,
"published_at": "2026-09-29T16:17:10.887+00:00"
}