baresip re up to 4.8.0 WebSocket src/websock/websock.c websock_decode len integer overflow

Summaryinfo

A vulnerability identified as critical has been detected in baresip re up to 4.8.0. This affects the function websock_decode of the file src/websock/websock.c of the component WebSocket. The manipulation of the argument len leads to integer overflow. This vulnerability is listed as CVE-2026-50161. The attack may be initiated remotely. There is no available exploit.

Detailsinfo

A vulnerability was found in baresip re up to 4.8.0 and classified as critical. This issue affects the function websock_decode of the file src/websock/websock.c of the component WebSocket. The manipulation of the argument len with an unknown input leads to a integer overflow vulnerability. Using CWE to declare the problem leads to CWE-190. The product performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-50161 since 06/03/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 4.8.1 eliminates this vulnerability.

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Productinfo

Vendor

• baresip

Name

• re

Version

• 4.0
• 4.1
• 4.2
• 4.3
• 4.4
• 4.5
• 4.6
• 4.7
• 4.8.0

Website

• Product: https://github.com/baresip/re/

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