CVE-2026-50161

libre: Integer overflow in websock_decode() masked frame length check leads to heap buffer overflow

Published Aug 18, 2026 CVSS 4.0 · 9.3 Critical EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Baresip
Baresip re
Vendors & Products Baresip
Baresip re
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title libre: Integer overflow in websock_decode() masked frame length check leads to heap buffer overflow
Weaknesses CWE-190
CWE-787
References
Metrics cvssV4_0

{'score': 9.3, 'vector': '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Aug 19, 2026, 3:11 PM
Reserved
Jun 3, 2026, 8:54 PM
Status
Deferred
Published
Aug 18, 2026, 6:17 PM
Modified
Oct 22, 2026, 10:10 PM