GHSA-8H6X-H86X-75WH
Vulnerability from github – Published: 2026-09-22 20:34 – Updated: 2026-09-22 20:34Summary
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/sipgo@v1.4.0/sip/transport_ws.go:400 +0x2df
github.com/emiago/sipgo/sip.(*TransportWS).readConnection(...)
/path/to/pkg/mod/github.com/emiago/sipgo@v1.4.0/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/sipgo@v1.4.0/sip/transport_ws.go:167 +0x268
Suggested Fix
Set MaxFrameSize on the wsutil.NewReader.
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.
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 1.4.2"
},
"package": {
"ecosystem": "Go",
"name": "github.com/emiago/sipgo"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.4.3"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-77322"
],
"database_specific": {
"cwe_ids": [
"CWE-789"
],
"github_reviewed": true,
"github_reviewed_at": "2026-09-22T20:34:30Z",
"nvd_published_at": null,
"severity": "HIGH"
},
"details": "### Summary\n\nThe WebSocket transport allocates a buffer from the frame payload length before validating its size, which can lead to an unauthenticated DoS.\n\n### Details\n\n`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):\n\n```go\ndata := make([]byte, header.Length) // header.Length is client-controlled, up to 2^63-1 (int64)\n```\n\n- `NextFrame()` reads only the frame header and never checks the length: `wsutil.NewReader` is created with no [`MaxFrameSize`](https://pkg.go.dev/github.com/gobwas/ws@v1.3.2/wsutil#Reader.MaxFrameSize) (`0` = unlimited). `ParseMaxMessageLength` applies only downstream, not here.\n- A value above the max slice size (e.g. `2^63-1`) panics `make`. sipgo does not recover from this panic, so it crashes the whole server process.\n\n### PoC\n\nTested on emiago/sipgo v1.4.0 (latest).\n\nAfter 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.\n\n```\n0x81 FIN + text opcode\n0xFF MASK bit + length marker 127 (8-byte length follows)\n0x7F FF FF FF FF FF FF FF declared length = 2^63-1 -\u003e make panics (crash)\n\u003c4-byte masking key\u003e\n(no payload)\n```\n\nThis crashes the server process:\n\n```\npanic: runtime error: makeslice: len out of range\n\ngoroutine 23 [running]:\ngithub.com/emiago/sipgo/sip.(*WSConnection).Read(...)\n /path/to/pkg/mod/github.com/emiago/sipgo@v1.4.0/sip/transport_ws.go:400 +0x2df\ngithub.com/emiago/sipgo/sip.(*TransportWS).readConnection(...)\n /path/to/pkg/mod/github.com/emiago/sipgo@v1.4.0/sip/transport_ws.go:194 +0x266\ncreated by github.com/emiago/sipgo/sip.(*TransportWS).initConnection in goroutine 21\n /path/to/pkg/mod/github.com/emiago/sipgo@v1.4.0/sip/transport_ws.go:167 +0x268\n```\n\n### Suggested Fix\n\nSet [`MaxFrameSize`](https://pkg.go.dev/github.com/gobwas/ws@v1.3.2/wsutil#Reader.MaxFrameSize) on the `wsutil.NewReader`.\n\n### Impact\n\nUnauthenticated 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.",
"id": "GHSA-8h6x-h86x-75wh",
"modified": "2026-09-22T20:34:30Z",
"published": "2026-09-22T20:34:30Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/emiago/sipgo/security/advisories/GHSA-8h6x-h86x-75wh"
},
{
"type": "WEB",
"url": "https://github.com/emiago/sipgo/commit/769e4bc958376e2363566c8f7042202b410becdc"
},
{
"type": "PACKAGE",
"url": "https://github.com/emiago/sipgo"
},
{
"type": "WEB",
"url": "https://github.com/emiago/sipgo/releases/tag/v1.4.3"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
],
"summary": "SIPGO: DoS via unvalidated WebSocket frame length"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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