CVE-2026-31812: Quinn proto Denial of Service Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-6xvm-j4wr-6v98",
  "modified" : "2026-03-11T05:46:01Z",
  "published" : "2026-03-11T00:09:19Z",
  "aliases" : [ "CVE-2026-31812" ],
  "summary" : "Quinn affected by unauthenticated remote DoS via panic in QUIC transport parameter parsing",
  "details" : "### Summary\nA remote, unauthenticated attacker can trigger a denial of service in applications using vulnerable `quinn` versions by sending a crafted QUIC Initial packet containing malformed `quic_transport_parameters`. `In quinn-proto` parsing logic, attacker-controlled varints are decoded with `unwrap()`, so truncated encodings cause `Err(UnexpectedEnd)` and `panic`. This is reachable over the network with a single packet and no prior trust or authentication.\n\n### Details\nThe issue is panic-on-untrusted-input in QUIC transport parameter parsing.\nIn `quinn-proto` (observed in `quinn-proto 0.11.13`), parsing of some transport parameters uses a fallible varint decode followed by `unwrap()`. For malformed/truncated parameter values, decode returns `UnexpectedEnd`, and `unwrap()` panics.\n\n#### Observed output:\n```\nthread 'tokio-rt-worker' (2366474) panicked at quinn-proto/src/transport_parameters.rs:473:67:\ncalled `Result::unwrap()` on an `Err` value: UnexpectedEnd\n```\n\n### PoC\n#### Reproduces against the upstream Quinn server example.\n1. Start server:\n```\ncargo run --example server -- ./\n```\n2. Prepare PoC client environment:\n```\npython3 -m venv .venv\nsource .venv/bin/activate\npip install aioquic\n```\n3. Run PoC script [attack.py](https://github.com/user-attachments/files/25741713/attack.py) against server QUIC listener (default example target shown):\n```\npython attack.py\n```\n#### Observed output\n```\nthread 'tokio-rt-worker' (2366903) panicked at quinn-proto/src/transport_parameters.rs:473:67:\ncalled `Result::unwrap()` on an `Err` value: UnexpectedEnd\n```\n\n\n\n### Impact\nVulnerability type: Remote Denial of Service (panic/crash)\nAttack requirements:  Network reachability to UDP QUIC listener\nAuthentication/privileges: None\nWho is impacted: Any server/application using affected `quinn/quinn-proto` versions where this parse path is reachable; process-level impact depends on integration panic handling policy\n\n\nThis vulnerability was originally submitted by @revofusion to the Ethereum Foundation bug bounty program",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "crates.io",
      "name" : "quinn-proto"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.11.14"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/quinn-rs/quinn/security/advisories/GHSA-6xvm-j4wr-6v98"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-31812"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/quinn-rs/quinn/pull/2559"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/quinn-rs/quinn"
  }, {
    "type" : "WEB",
    "url" : "https://rustsec.org/advisories/RUSTSEC-2026-0037.html"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-248" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-11T00:09:19Z",
    "nvd_published_at" : "2026-03-10T22:16:18Z"
  }
}