libre — security advisory
libre is a generic library for real-time communications with asynchronous input and output support. Prior to 4.8.1, the websock_decode() function in src/websock/websock.c contains an integer overflow when validating a masked WebSocket frame that uses the 64-bit extended length encoding. The expression 4 + hdr->len can wrap when hdr->len is close to UINT64_MAX, causing the mbuf_get_left() bounds check to pass. The subsequent XOR unmasking loop then writes beyond the heap buffer. Applications using websock_accept() or websock_accept_proto() to implement a WebSocket server are affected, and exploitation can cause attacker-controlled heap corruption or denial of service after the HTTP WebSocket upgrade handshake. This issue is fixed in version 4.8.1.
- Products
- libre
- Affected versions
- 1.1.0-1, 1.1.0-2, 2.0.1-1, 2.0.1-1~exp1, 2.0.1-1~exp2, 2.0.1-2, 2.0.1-3, 2.0.1-4
- Fixed versions
- 2.0.1-4
- CVEs
- CVE-2026-50161
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 03:49 UTC · Revision 1
Source evidence
libre is a generic library for real-time communications with asynchronous input and output support. Prior to 4.8.1, the websock_decode() function in src/websock/websock.c contains an integer overflow when validating a masked WebSocket frame that uses the 64-bit extended length encoding. The expression 4 + hdr->len can wrap when hdr->len is close to UINT64_MAX, causing the mbuf_get_left() bounds check to pass. The subsequent XOR unmasking loop then writes beyond the heap buffer. Applications using websock_accept() or websock_accept_proto() to implement a WebSocket server are affected, and exploitation can cause attacker-controlled heap corruption or denial of service after the HTTP WebSocket upgrade handshake. This issue is fixed in version 4.8.1.
osv:DEBIAN-CVE-2026-50161
libre
Fixed versions: Not specified
libre
Fixed versions: Not specified
libre
Fixed versions: 2.0.1-4
Complete source record
{
"id": "e23e181043703a859d42781d6f8163096fd9d7ac99a6862b4395d85e81c45404",
"url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-50161",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "DEBIAN-CVE-2026-50161",
"summary": "libre is a generic library for real-time communications with asynchronous input and output support. Prior to 4.8.1, the websock_decode() function in src/websock/websock.c contains an integer overflow when validating a masked WebSocket frame that uses the 64-bit extended length encoding. The expression 4 + hdr->len can wrap when hdr->len is close to UINT64_MAX, causing the mbuf_get_left() bounds check to pass. The subsequent XOR unmasking loop then writes beyond the heap buffer. Applications using websock_accept() or websock_accept_proto() to implement a WebSocket server are affected, and exploitation can cause attacker-controlled heap corruption or denial of service after the HTTP WebSocket upgrade handshake. This issue is fixed in version 4.8.1.",
"evidence": "osv:DEBIAN-CVE-2026-50161",
"products": [
{
"name": {
"value": "libre",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.1.0-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.1.0-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.0.1-1",
"evidence": "/affected/0/versions"
},
{
"value": "2.0.1-1~exp1",
"evidence": "/affected/0/versions"
},
{
"value": "2.0.1-1~exp2",
"evidence": "/affected/0/versions"
},
{
"value": "2.0.1-2",
"evidence": "/affected/0/versions"
},
{
"value": "2.0.1-3",
"evidence": "/affected/0/versions"
},
{
"value": "2.0.1-4",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
"value": "libre",
"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.0.1-3",
"evidence": "/affected/1/versions"
},
{
"value": "2.0.1-4",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
"value": "libre",
"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [
{
"value": "2.0.1-4",
"evidence": "/affected/2/ranges"
}
],
"affected_versions": [
{
"value": "2.0.1-3",
"evidence": "/affected/2/versions"
}
]
}
],
"severity": "critical",
"structured": {
"id": "DEBIAN-CVE-2026-50161",
"aliases": [
"DEBIAN-CVE-2026-50161"
],
"metrics": [
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libre",
"purl": "pkg:deb/debian/libre?arch=source&distro=bookworm",
"ecosystem": "Debian:12"
},
"versions": [
"1.1.0-1",
"1.1.0-2",
"2.0.1-1",
"2.0.1-1~exp1",
"2.0.1-1~exp2",
"2.0.1-2",
"2.0.1-3",
"2.0.1-4"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-50161.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "libre",
"purl": "pkg:deb/debian/libre?arch=source&distro=trixie",
"ecosystem": "Debian:13"
},
"versions": [
"2.0.1-3",
"2.0.1-4"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-50161.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
},
{
"fixed": "2.0.1-4"
}
]
}
],
"package": {
"name": "libre",
"purl": "pkg:deb/debian/libre?arch=source&distro=forky",
"ecosystem": "Debian:14"
},
"versions": [
"2.0.1-3"
],
"database_specific": {
"source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-50161.json"
},
"ecosystem_specific": {
"urgency": "not yet assigned"
}
}
],
"modified": "2026-10-24T05:01:23.525854803Z",
"provider": "osv",
"upstream": [
"CVE-2026-50161"
],
"references": [
"https://security-tracker.debian.org/tracker/CVE-2026-50161"
]
},
"related_cves": [
{
"value": "CVE-2026-50161",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 428209,
"published_at": "2026-08-18T18:17:53.38+00:00"
}