Pre-shared key mode transmits the TGK in cleartext, exposing the SRTP master key

{
  "id": "6e969a0487e9c21de1199185aa04bafb2c86d88027de68042187474fb3fd160d",
  "url": "https://osv.dev/vulnerability/RUSTSEC-2026-0335",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Pre-shared key mode transmits the TGK in cleartext, exposing the SRTP master key",
    "summary": "`mykey` implements MIKEY (RFC 3830) for SRTP key exchange. Pre-shared key mode transmitted the TEK Generation Key (TGK) in the clear. `MikeyMessage::new_psk_init` built its KEMAC payload with `EncAlg::Null` and placed the TGK in `enc_data` verbatim. Anyone able to read a PSK-Init message therefore recovers the TGK — and so the SRTP master key — **without knowing the pre-shared key**. The transmitted value was never even used by the receiver: `complete_psk` re-derived the TGK from the pre-shared key and ignored `enc_data` entirely. The field was write-only; it provided nothing and disclosed everything. A second consequence: the message authentication key was derived from the TGK rather than from the pre-shared key, so an attacker who read the TGK off the wire could also forge a valid message MAC. Integrity was lost along with confidentiality. That aspect is tracked separately as GHSA-xq78-wvcv-hqvj. ## Exploitability A MIKEY message is normally distributed as an SDP `a=key-mgmt:mikey` attribute, which in AES67 and SMPTE ST 2110 deployments is typically announced over SAP multicast. A passive listener on the media network recovers the session key with no active attack and no credentials. RFC 3830 §4.2.3 permits NULL encryption only where \"the underlying protocols can guarantee security\", and warns to use it with caution. An SDP file or a SAP announcement is not such a channel. ## The fix Pre-shared key mode now follows RFC 3830 §3.1 as key *transport*: the initiator generates a",
    "evidence": "osv:RUSTSEC-2026-0335",
    "products": [
      {
        "name": {
          "value": "mykey",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "2.0.0",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "critical",
    "structured": {
      "id": "RUSTSEC-2026-0335",
      "aliases": [
        "GHSA-fwjg-cm92-j3hj",
        "RUSTSEC-2026-0335"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0.0.0-0"
                },
                {
                  "fixed": "2.0.0"
                }
              ]
            }
          ],
          "package": {
            "name": "mykey",
            "purl": "pkg:cargo/mykey",
            "ecosystem": "crates.io"
          },
          "database_specific": {
            "cvss": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
            "source": "https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2026-0335.json",
            "categories": [
              "crypto-failure"
            ],
            "informational": null
          },
          "ecosystem_specific": {
            "affects": {
              "os": [],
              "arch": [],
              "functions": []
            },
            "affected_functions": null
          }
        }
      ],
      "modified": "2026-10-12T09:15:02.450106103Z",
      "provider": "osv",
      "references": [
        "https://crates.io/crates/mykey",
        "https://rustsec.org/advisories/RUSTSEC-2026-0335.html",
        "https://github.com/waxspin/mykey/pull/25"
      ],
      "provider_metadata": {
        "license": "CC0-1.0"
      }
    },
    "related_cves": [],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 298668,
  "published_at": "2026-10-09T12:00:00+00:00"
}