CVE-2026-50161

CVSS 9.3 (critical) · published 2026-08-18

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.

Weakness: CWE-190, CWE-787

Source: NVD CVE-2026-50161

References

• https://github.com/baresip/re/commit/718b92615c7963670d26c1a2b246968b58d782e8
• https://github.com/baresip/re/pull/1584
• https://github.com/baresip/re/releases/tag/v4.8.1
• https://github.com/baresip/re/security/advisories/GHSA-hvxv-v2gp-v93h

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