Critical
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
- 0.4.14-1, 0.4.14-2, 0.4.14-3, 0.4.14-4, 0.5.4-3ubuntu1, 0.5.5-1ubuntu1, 0.5.6-1ubuntu1, 0.5.6-1ubuntu2, 0.6.0-4, 1.1.0-1, 1.1.0-1build1, 1.1.0-1build2, 1.1.0-1build3, 1.1.0-1build4, 2.0.1-3, 2.0.1-3build1, 2.0.1-3ubuntu1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-50161
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:26 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:UBUNTU-CVE-2026-50161
libre
Fixed versions: Not specified
libre
Fixed versions: Not specified
libre
Fixed versions: Not specified
libre
Fixed versions: Not specified
libre
Fixed versions: Not specified
libre
Fixed versions: Not specified
libre
Fixed versions: Not specified
Complete source record
{
"id": "5fff06c21b3eff9acd59100922b894f89b097c1ca9c395ad8cf3e118414c2d19",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-50161",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-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:UBUNTU-CVE-2026-50161",
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],
"severity": "critical",
"structured": {
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"aliases": [
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"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"
},
{
"type": "Ubuntu",
"score": "medium"
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"affected": [
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"0.5.6-1ubuntu1",
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],
"database_specific": {
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},
"ecosystem_specific": {
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},
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],
"modified": "2026-10-17T12:58:32.553307733Z",
"provider": "osv",
"upstream": [
"CVE-2026-50161"
],
"references": [
"https://ubuntu.com/security/CVE-2026-50161",
"https://www.cve.org/CVERecord?id=CVE-2026-50161",
"https://github.com/baresip/re/security/advisories/GHSA-hvxv-v2gp-v93h",
"https://github.com/baresip/re/pull/1584"
]
},
"related_cves": [
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"evidence": "/upstream"
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],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 358724,
"published_at": "2026-08-18T18:17:00+00:00"
}