Summary
SIPGO: DoS via unvalidated WebSocket frame length
The WebSocket transport allocates a buffer from the frame payload length before validating its size, which can lead to an unauthenticated DoS.
Details
WSConnection.Read allocates a buffer from the declared WebSocket frame length before reading the payload (https://github.com/emiago/sipgo/blob/v1.4.0/sip/transport_ws.go#L400):
data := make([]byte, header.Length) // header.Length is client-controlled, up to 2^63-1 (int64)
NextFrame()reads only the frame header and never checks the length:wsutil.NewReaderis created with noMaxFrameSize(0= unlimited).ParseMaxMessageLengthapplies only downstream, not here.- A value above the max slice size (e.g.
2^63-1) panicsmake. sipgo does not recover from this panic, so it crashes the whole server process.
PoC
Tested on emiago/sipgo v1.4.0 (latest).
After a normal WebSocket handshake, send one masked text frame consisting of the header only (no payload), declaring a huge length. The allocation runs as soon as the header is read.
0x81 FIN + text opcode
0xFF MASK bit + length marker 127 (8-byte length follows)
0x7F FF FF FF FF FF FF FF declared length = 2^63-1 -> make panics (crash)
<4-byte masking key>
(no payload)
This crashes the server process:
panic: runtime error: makeslice: len out of range
goroutine 23 [running]:
github.com/emiago/sipgo/sip.(*WSConnection).Read(...)
/path/to/pkg/mod/github.com/emiago/[email protected]/sip/transport_ws.go:400 +0x2df
github.com/emiago/sipgo/sip.(*TransportWS).readConnection(...)
/path/to/pkg/mod/github.com/emiago/[email protected]/sip/transport_ws.go:194 +0x266
created by github.com/emiago/sipgo/sip.(*TransportWS).initConnection in goroutine 21
/path/to/pkg/mod/github.com/emiago/[email protected]/sip/transport_ws.go:167 +0x268
Impact
Unauthenticated DoS. Any service using sipgo with a WS/WSS transport can be crashed by a single frame (panic), or forced to run out of memory.
CVE-2026-77322 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 (1.4.3); 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
Set MaxFrameSize on the wsutil.NewReader.
Frequently Asked Questions
- What is CVE-2026-77322? CVE-2026-77322 is a high-severity security vulnerability in github.com/emiago/sipgo (go), affecting versions <= 1.4.2. It is fixed in 1.4.3.
- How severe is CVE-2026-77322? CVE-2026-77322 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-2026-77322? github.com/emiago/sipgo (go) versions <= 1.4.2 is affected.
- Is there a fix for CVE-2026-77322? Yes. CVE-2026-77322 is fixed in 1.4.3. Upgrade to this version or later.
- Is CVE-2026-77322 exploitable, and should I be worried? Whether CVE-2026-77322 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-2026-77322 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-2026-77322? Upgrade
github.com/emiago/sipgoto 1.4.3 or later.